Can Online Teaching of Radiographic Anatomy Replace Conventional On-Site Teaching? A Randomized Controlled Study.

Different modalities such as lectures, dissections, 3D models, and online learning are used for teaching anatomy. To date, online learning has been considered a useful additional didactic tool. This study aimed to compare veterinary students' performance in radiographic anatomy (radio-anatomy) after online or classroom-based teaching to assess the extent to which the two methods were interchangeable. Three strategies were compared in a cohort of 83 learners. Students were committed to online learning only, online learning with the use of specimen equine bones, or learning on conventional radiographs with specimen equine bones. At baseline (pre-test), scores from a mental rotation test and radio-anatomy knowledge test were similar between groups. After training (post-test), scores in mental rotation and radio-anatomy significantly increased by 6.7/40 units (95% CI: 5.2-8.2; p < .001) and 5.1/20 units (95% CI: 4.3-5.9; p < .001), respectively. There was no difference in scores for mental rotation and radio-anatomy knowledge between groups at post-test. Gender influenced the mental rotation, with men scoring significantly higher than women at pre-test (M = 23.0, SD = 8.8 vs. M = 16.5, SD = 6.9; p = .001) and post-test (M = 32.1, SD = 5.5 vs. M = 22.7, SD = 8.6; p < .001). However, radio-anatomy knowledge was not influenced by gender. These results suggest radio-anatomy teaching can be safely achieved with either conventional radiographs or online resources. This is of interest since, due to the COVID-19 outbreak, rapidly changing from on-site to online methods for teaching veterinary medical education proved necessary.

Evaluation of a 3D Computer Model of the Equine Paranasal Sinuses as a Tool for Veterinary Anatomy Education.

Detailed knowledge of anatomical systems is vital for clinical veterinary practice. However, students often find it difficult to transfer skills learned from textbooks to real-life practice. In this study, a three-dimensional computer model representing equine paranasal sinus anatomy (3D-ESM) was created and evaluated for its contribution to student understanding of the 3D dynamic nature of the system. Veterinary students and equine professionals at the University of Bristol were randomly allocated into experimental (3D model) and control (2D lecture) groups. A pre-/post-study design was used to evaluate the efficacy of the 3D model through a pre-/post-multiple-choice question (MCQ) anatomical knowledge exam and a pre-/post-questionnaire gathering information on participant demographics, confidence, and satisfaction. No statistically significant difference was found between 3D and 2D groups' post-MCQ exam scores (t39 = 1.289, p = .205). 3D group participant feedback was more positive than 2D group feedback, and 3D group satisfaction scores on Likert questions were significantly higher (t118 = -5.196, p < .001). Additionally, confidence scores were significantly higher in the 3D group than in the 2D group immediately following the study (p < .05). Participants' open-text responses indicated they found the 3D model helpful in learning the complex anatomy of the equine paranasal sinuses. Findings suggest the 3D-ESM is an effective educational tool that aids in confidence, enjoyment, and knowledge acquisition. Though it was not better than traditional methods in terms of anatomy knowledge exam scores, the model is a valuable inclusion into the veterinary anatomy curriculum.

Anatomy education in Ottoman-Turkish veterinary schools during 19th century and Papier-Mache models.

Veterinary medicine was recognized as a scientific discipline for the first time in 1762 in France. After a while, the first Ottoman-Turkish veterinary school was established in 1842, primarily for the improvement and welfare of army horses. There is not much detailed information about the content of the anatomy education and materials in the early days of veterinary schools apart from the anecdote that Gurlt's illustrated anatomy books were being used. The purpose of this study is to research anatomy education in the 19th century, when Ottoman-Turkish veterinary medicine was established, as well as the Papier-mâché models used in anatomy education, searching primary and secondary sources that can be accessed online. It has been determined that the normal and pathological anatomy models of humans and various domestic animals made by Dr. Auzoux were ordered to be used in the anatomy education of the newly established veterinary schools. The whereabouts of these models, which did not reference in publications until now, are unknown. However, examining these models is regarded to be crucial for understanding the veterinary anatomy perspective and educational content of the period.

Effectiveness of a Student-Developed Instructional Video in Learning the Anatomy of the Equine Distal Limb.

The anatomy of the equine distal limb (EDL) is both complex and important to veterinary clinical practice. First-year veterinary students (VM1s) often struggle to adequately understand it. Two third-year veterinary students collaborated with instructors to create an instructional video to facilitate first-year students' comprehension of EDL anatomy. The video was offered to all VM1s. Learning outcomes were assessed via practical exams. Exam scores on EDL structures were compared between students who did (video) and students who did not (no video) watch the video. Students' laboratory experiences and confidence were evaluated with a post-exam survey. The third-year students documented their experiences while producing the video. Eighty percent of VM1s viewed the video; 91% rated the video as very valuable. The video improved student confidence during the practical exam by 9%, and 89% of surveyed students indicated the video positively impacted their exam grade. One item score was significantly improved in the video group (p < .001), as was the score of the five questions combined (p < .001). As expected, overall practical exam scores were not statistically different. Student collaborators indicated that participation reinforced their knowledge while enhancing their professional development. Student collaboration was a beneficial strategy for instructional support development that positively impacted student affect and also generated opportunities for the involved students' professional growth.

Anatomy in Practice: How Do Equine and Production Animal Veterinarians Apply Anatomy in Primary Care Settings?

To successfully prepare veterinary undergraduates for the workplace, it is critical that anatomy educators consider the context in which developing knowledge and skills will be applied. This study aimed to establish how farm animal and equine general practitioners use anatomy and related skills within their daily work. Qualitative ethnographic data in the form of observations and semi-structured interviews were collected from 12 veterinarians working in equine or farm animal first-opinion practice. Data underwent thematic analysis using a grounded theory approach. The five themes identified were relevant to both equine and farm animal veterinarians and represented the breadth and complexity of anatomy, its importance for professional and practical competence, as well as the requirement for continuous learning. The centrality and broad and multifaceted nature of anatomy was found to challenge equine and farm animal veterinarians, highlighting that essential anatomy knowledge and related skills are vital for their professional and practical competence. This aligns with the previously described experiences of companion animal clinicians. In equine practice, the complexity of anatomical knowledge required was particularly high, especially in relation to diagnostic imaging and assessing normal variation. This resulted in greater importance being placed on formal and informal professional development opportunities. For farm animal clinicians, anatomy application in the context of necropsy and euthanasia was particularly noted. Our findings allow anatomy educators to design appropriate and effective learning opportunities to ensure that veterinary graduates are equipped with the skills, knowledge, and resources required to succeed in first-opinion veterinary practice.

Novel Method to Manage Student Questions in the Anatomy Laboratory Using a Virtual Meeting Platform.

Large class sizes and often few instructors in anatomy courses make it challenging for student laboratory groups to have their questions addressed in a timely manner. Instructors are often unaware of the number of requests for assistance, as well as the order in which assistance is requested, and students often spend a long time waiting for an instructor to become available. As a result of brainstorming with some of our students, a call button system of sorts was suggested. Instructors in consultation with the college's IT department came up with the idea of using Zoom Meetings question and answer (Q&A) feature to manage student questions. Zoom allows one to broadcast a Zoom Meeting to up to 50,000 participant attendees, and instructors, logged in as panelists (on a mobile device, e.g., iPad), can interact with the student attendees via the Q&A feature. The students join the webinar using their dissection table number as their ID and request assistance in the Q&A. These requests show up with a time stamp and are automatically queued on the panelist's Q&A window. Instructors employ the type answer feature to acknowledge the question by typing in their respective initials, which can be seen live by the other instructors (panelists). This allows student questions to be queued so that the instructors can address them in a timely, first-in/first-out order. Student feedback regarding the use of this system for the Small Animal Anatomy course was positive.

Domestic pig head and neck arteries from the viewpoint of imaging methods and experimental surgery

The aim of this paper is to summarize the current knowledge of the anatomy of domestic pig head and neck arteries for the needs of experimental surgery and imaging methods in biomedical research and translational medicine. The potential of this large animal model seems to be valuable also for the xenotransplantation of certain organs. Demands for the knowledge of morphological differences between analogous human structures and particular breeds are growing also in connection with the need for more precise planning of experiments or interpretation of the results. Deepening anatomical knowledge is allowed also by the development of imaging methods. The search was performed using the keywords "domestic pig" and "arteries of the head and neck" in the MEDLINE database, PubMed interface.

Canine Skull Digitalization and Three-Dimensional Printing as an Educational Tool for Anatomical Study.

This article aims to standardize 3D scanning and printing of dog skulls for educational use and evaluate the effectiveness of these anatomical printed models for a veterinary anatomy course. Skulls were selected for scanning and creating 3D-printed models through Fused Deposition Modeling using acrylonitrile-butadiene-styrene. After a lecture on skull anatomy, the 3D-printed and real skull models were introduced during the practical bone class to 140 students. A bone anatomy practical test was conducted after a month; it consisted in identifying previously marked anatomical structures of the skull bones. The students were divided into two groups for the exam; the first group of students took the test on the real skulls, whereas the second group of students took the test on 3D-printed skulls. The students' performance was evaluated using similar practical examination questions. At the end of the course, these students were asked to answer a brief questionnaire about their individual experiences. The results showed that the anatomical structures of the 3D-printed skulls were similar to the real skulls. There was no significant difference between the test scores of the students that did their test using the real skulls and those using 3D prints. In conclusion, it was possible to construct a dynamic and printed digital 3D collection for studies of the comparative anatomy of canine skull species from real skulls, suggesting that 3D-digitalized and-printed skulls can be used as tools in veterinary anatomy teaching.

The Evolution of Educational Technology in Veterinary Anatomy Education.

"All learning is in the learner, not the teacher." Plato was right. The adage has passed the test of time and is still true in an era where technology accompanies us in not only professional but also recreational life every day, everywhere. On the other hand, the learner has evolved and so have the sources being used to satisfy curiosity and learning. It therefore appears intuitive to embrace these technological advances to bring knowledge to our pupils with the aim to facilitate learning and improve performance. It must be clear that these technologies are not intended to replace but rather consolidate knowledge partly acquired during more conventional teaching of anatomy. Veterinary medicine is no outlier. Educating students to the complexity of anatomy in multiple species requires that three-dimensional concepts be taught and understood accurately if appropriate treatment is to be set in place thereafter. Veterinary anatomy education has up to recently walked diligently in the footsteps of John Hunter's medical teaching using specimens, textbooks, and drawings. The discipline has yet to embrace fully the benefits of advancement being made in technology for the benefit of its learners. Three-dimensional representation of anatomy is undeniably a logical and correct way to teach whether it is through the demonstration of cadaveric specimen or alternate reality using smartphones, tablets, headsets or other digital media. Here we review some key aspects of the evolution of educational technology in veterinary anatomy.

Turkish Undergraduate Veterinary Students' Attitudes to Use of Animals and Other Teaching Alternatives for Learning Anatomy.

This study aimed to investigate the views of first-year veterinary students in Turkey from six veterinary faculties on their anatomy courses and to evaluate their perceptions of the uses of animals and other teaching alternatives from an ethical perspective. The study sample included a total of 293 veterinary students studying in the provinces of Ankara, Burdur, Diyarbakir, Kars, Konya, and Tekirdag. The 38-item instrument tool developed by the researchers consisted of three sections and was administered to volunteer student participants. All the data were statistically analyzed, and normal distribution of the scores obtained in the attitude scales was determined using the Kolmogorov-Smirnov Z test (KSZ). The 20 items in the Anatomy Scale had an arithmetic mean of 3.48 and thus indicated an average rating of agree. The most challenging topic was found by 40.9% to be "the nervous system." The most useful material in facilitating the learning process was rated by 24.1% to be "the anatomy book." The 11 items in the Cadaver Scale had an arithmetic mean of 3.77, indicating an average rating of agree. The highest arithmetic mean score was for the item "Using cadavers is a must for the anatomy course" with a mean of 4.66, indicating their strong agreement with this view. The veterinary students' perspective emphasized that the combination of cadavers and the anatomy book contributed to their learning of anatomy.

An Anatomy Pre-Course Predicts Student Performance in a Professional Veterinary Anatomy Curriculum.

Little to no correlation has been identified between previous related undergraduate coursework or outcomes on standardized tests and performance in a veterinary curriculum, including anatomy coursework. Therefore, a relatively simplistic method to predict student performance before entrance would be advantageous to many. The purpose of this study was to evaluate whether there is a correlation between performance in a veterinary anatomy pre-course and subsequent performance within a professional anatomy curriculum. Incoming first-year veterinary students at the Louisiana State University School of Veterinary Medicine were asked to participate in a free weeklong pre-course, before the start of the semester. The pre-course covered the musculoskeletal anatomy of the canine thoracic limb using dissection-based methods. Student performance, as evaluated by test grades in the pre-course, did indeed correlate with test grades in professional veterinary anatomy courses. A significant and positive correlation was identified between pre-course final exam performance and performance on examinations in each of 3 professional anatomy courses. Qualitative analyses of student comments pertaining to their experience within the pre-course indicated differences in the perceived benefits of the pre-course between high-, middle-, and low-performing students. These varied perceptions may provide predictive feedback as well as guidance for supporting lower performing students. Together, these results indicate that performance in a weeklong pre-course covering only a small portion of canine anatomy is a strong predictor of performance within a professional anatomy curriculum. In addition, the pre-course differentially affected student perceptions of their learning experience.

Saturated salt solution: a further step to a formaldehyde-free embalming method for veterinary gross anatomy.

In the field of veterinary anatomy, most of the specimens used in practical sessions are perfused with fixatives. Thus, they can be used for a longer time, reducing the number of animals for educational purposes. Formalin is the most commonly used fixative, consisting of a 37% formaldehyde solution. However, formaldehyde is a powerful irritant of the eyes and airways and is considered carcinogenic, causing nasopharyngeal cancer in exposed workers and professionals. In the present study, we explored an alternative method to avoid the use of formaldehyde in specimens used for gross anatomy practical sessions. We propose an inexpensive, non-toxic fixative that is available worldwide, such as sea salt. This method consists of a continuous perfusion of saturated salt solution for a period of 6-8 h, enabling drainage of the solution to avoid a weight increase of the specimen, and allowing salt to be retained in the tissue. The method is based on recirculation of the saturated salt solution instead of maceration. Perfused specimens retained their natural consistency and joint mobility, with no blood, resembling a piece of meat from the slaughterhouse. They could be used immediately without a maceration period, or stored in the fridge until use and then kept in a bath of saturated salt solution for future conservation. In the case of the former, no refrigeration was needed. The specimens did not have an irritating or offensive smell, and could be used for long sessions (several hours per day) and stored for long periods. However, the blood vessels used for perfusion determine the results: a less invasive approach (through common carotid arteries) gave good preservation of the musculoskeletal system, whereas more invasive access to cannulate the abdominal aorta and vena cava caudalis was required to achieve better preservation of the viscera. In conclusion, we propose that perfusion followed by immersion in a saturated salt solution is a good alternative method for the preservation of specimens used in the practical teaching of gross veterinary anatomy. It is a very simple and inexpensive technique, and is much healthier for users than traditional formalin. Moreover, specimens can be preserved for prolonged periods, and maintain a similar appearance and consistency to fresh material.

Spatial and Visual Reasoning: Do These Abilities Improve in First-Year Veterinary Medical Students Exposed to an Integrated Curriculum?

Spatial visualization ability refers to the human cognitive ability to form, retrieve, and manipulate mental models of spatial nature. Visual reasoning ability has been linked to spatial ability. There is currently limited information about how entry-level spatial and visual reasoning abilities may predict veterinary anatomy performance or may be enhanced with progression through the veterinary anatomy content in an integrated curriculum. The present study made use of two tests that measure spatial ability and one test that measures visual reasoning ability in veterinary students: Guay's Visualization of Views Test, adapted version (GVVT), the Mental Rotations Test (MRT), and Raven's Advanced Progressive Matrices Test, short form (RavenT). The tests were given to the entering class of veterinary students during their orientation week and at week 32 in the veterinary medical curriculum. Mean score on the MRT significantly increased from 15.2 to 20.1, and on the RavenT significantly increased from 7.5 to 8.8. When females only were evaluated, results were similar to the total class outcome; however, all three tests showed significant increases in mean scores. A positive correlation between the pre- and post-test scores was found for all three tests. The present results should be considered preliminary at best for associating anatomic learning in an integrated curriculum with spatial and visual reasoning abilities. Other components of the curriculum, for instance histology or physiology, could also influence the improved spatial visualization and visual reasoning test scores at week 32.

Acceptance of the bodypainting as supportive method to learn the surface locomotor apparatus anatomy of the horse.

Although bodypainting has been reported as a great resource for teaching surface anatomy of humans, its use in veterinary anatomy has not been scientifically reported. In the present study, bodypainting was performed on 4 horses for anatomy teaching purposes of the equine locomotor apparatus. We aimed to use the bodypainting method as an additional tool to classic teaching and to test the relevance of our purpose. Twenty one Brazilian veterinary students were given a 90-min session, which included a presentation of painted horses, with opportunities for the students to ask questions and to palpate anatomic locations on the horses. Based on a questionnaire, there was unanimous student satisfaction with this technique. Furthermore, student scores on practical tests to evaluate the attention retain given immediately before and 1 h after the session were 33.9 ± 19.8% and 69.0 ± 18.4%, respectively (p < 0.001). We concluded that bodypainting has great potential for support the classic lectures of the equine locomotor apparatus.

Students as teachers in an anatomy dissection course.

One way to improve students' learning outcomes and well-being is to change teaching practices to allow students to become more active participants. We used an anatomy dissection course to test a cooperative group work method in which first-year veterinary students took turns leading their peer group and were each responsible for teaching the anatomy of a particular topographic region. The important blood vessels, lymphatic system, and nerves of each region of the body were covered. Students felt that exploration of the entire topographic region helped them to acquire a comprehensive understanding of the respiratory apparatus and the cardiovascular and nervous systems. Assigning individual tasks to each group member resulted in sharing the workload equally. Open-ended comments revealed that support from other group members was important for the students' learning experience, but the results also offered insight into a lack of constructive criticism. While teaching was considered challenging, and even a stress factor that hindered learning for some students, group work was generally held to be supportive of learning. The results suggest that more thorough instruction of students in their group work and in their individual tasks is required. Some students experienced difficulty in expressing their concerns openly and in seeking guidance from teachers, demonstrating the need for further investigation regarding students' self-regulation skills. Comments from the open-ended responses suggest that use of a cooperative learning method in anatomy dissection courses not only deepens student understanding of a subject but also offers first-year students an opportunity to practice the generic skills that will be needed in their future profession.

Exploring alternatives for securing anatomical structures in capturing digital images: A comparative analysis.

Teaching veterinary anatomy using digital platforms requires improved image quality, which may influence the fixation process. This study aimed to compare four embalming solutions for high-colour-quality images of different tissues compared to the original image. Four equine left pelvic limbs were cut into metameres and divided equally for application of 10% formaldehyde, 96% glycerine, 33% hypersaturated NaCl solution and modified Larssen solution, respectively, which was maintained for 3 days. After drying for 3 days at room temperature, photographs were obtained at time 0 (T0), without any fixation process (original colour); time 1 (T1), immediately after removal from the solutions; and every 24 h for 3 days (T2-T4). The image colour quality was investigated by digitally evaluating the cortical bone, tendon and bone marrow using histograms and CIEDE2000 as well as by 10 specialists in an online survey. CIEDE2000 and histograms revealed that all fixation solutions changed the original tissue colour at all the time points (p < 0.0001). According to the specialists, the 33% saline solution produced the best results compared to the original one. The modified Larssen solution demonstrated better results for the tendon, marrow and cortical bone at T3 (p = 0.0015). Considering the colour of digital images, the modified Larssen solution provided the best results; however, the visual evaluation by the specialists revealed the 33% saline solution as the best.

Linear measurements and shape analysis in the calcaneus of selected dog breeds.

The vast array of dog breeds showcases a remarkable diversity that extends to osteological differences. Exploring these morphological distinctions and establishing reference data for various dog breeds are essential steps in comprehending the evolutionary changes that dogs have undergone. In this study, we conducted linear measurements of the calcaneus and performed shape analyses on selected dog breeds to elucidate distinctive characteristics among them. X-ray images of the calcaneus from six different dog breeds-Maltese Terrier, Toy Poodle, Pomeranian, Cavalier King Charles Spaniel, French Bulldog and Golden Retriever-were utilized for this investigation. Radiological images were obtained from a medio-lateral exposure, positioned 30 cm away from the x-ray device. From these images, four linear length measurements and two angle values were extracted. Additionally, a 2D geometric morphometric analysis was conducted using 32 semi landmarks placed on the radiological images. Linear measurements were assessed using ANOVA, while principal component analysis was employed to examine shape variations across all individuals. Shape differences between species were further elucidated through canonical variates analysis. The results revealed that the Golden Retriever exhibited the highest values for linear measurements, while the Pomeranian showed the lowest. Maltese Terriers displayed the highest dorsal calcaneal angle value. Notably, there were significant differences in calcaneal body length among all breeds, except for the Toy Poodle and Cavalier King Charles Spaniel. Moreover, Maltese Terriers exhibited statistically distinct angular measurements compared to other breeds. Principal component analysis unveiled that the first principal component explained 32.69% of the total variation, with the cranial edge of the calcaneal body being closer to the body in individuals with higher values. Shape variations also indicated that Golden Retrievers displayed a broader range of shapes compared to French Bulldogs, which exhibited a more conservative distribution. While there was no clear breed-specific distinction according to the first principal component, Cavalier King Charles Spaniels generally showed lower values. In canonical variates analysis, distinctions in calcaneal shape between species were apparent, with Golden Retrievers, Cavalier King Charles Spaniels and French Bulldogs displaying positive values for the first canonical variates. The highest Procrustes distance was observed between Maltese Terriers and Cavalier King Charles Spaniels. Notably, allometry was found to be statistically insignificant. This comprehensive study utilized both linear and geometric morphometric analyses based on x-ray images, yielding promising results. The integration of imaging systems in veterinary anatomy research presents numerous opportunities for studying animal welfare and health, utilizing various materials such as bones and cadavers. These advancements hold the potential for further enhancing our understanding of animal morphology and well-being.

Shape variation in cranium, mandible and teeth in selected mouse strains.

There are different strains of laboratory mouse used in many different fields. These strains differ anatomically. In order to determine these anatomical differences, shape analysis was conducted according to species. CD-1, C57bl/6 and Balb-c strains were preferred to study these differences. Forty-eight adult mouse strains belonging to these strains were utilized. The bones were photographed and geometric morphometry was applied to these photographs. Principal Component Analysis was applied to determine shape variations. In Principal component 1 for cranium, CD-1 and C57bl/6 strain groups showed different shape variations, while Balb-c strain group showed similar shape variations to the other strain groups. Principal Component 1 for the mandible separated the CD-1 and C57bl/6 strain groups in terms of shape variation. Principal Component 2 explained most of the variation between the C57bl/6 and CD-1 lineage groups. In PC1 for molars, the CD-1 group showed a different shape variation from the other groups. Mahalanobis distances and Procrustes distances were measured using Canonical variance analysis to explain the differences between the lineage groups. These measurements were statistically significant. For cranium, in canonical variate 1, CD-1 group of mouse and Balb-c group of mouse were separated from each other. In canonical variate 2, C57bl/6 group of mouse were separated from the other groups. For mandible, Balb-c group of mouse in canonical variate 1 and CD-1 group of mouse in canonical variate 2 were separated from the other groups. For molars, CD-1 group of mouse in canonical variate 1 and Balb-c group of mouse in canonical variate 2 were separated from the other groups. It was thought that these anatomical differences could be caused by genotypic factors as well as dietary differences and many different habits that would affect the way their muscles work.

Anatomical description of a pygmy sperm whale, Kogia breviceps (Cetacea: Kogiidae), pre-term calf using CT scan and 3D reconstructions.

Little is known about the biology of pygmy sperm whales, Kogia breviceps (De Blainville, 1838), being that most anatomical descriptions for the species derive from necropsy after stranding or from osteological material preserved in museums. This species is rarely seen despite its wide distribution, and its reproductive behaviour is still being investigated. The eventual occurrence of pregnant female strandings and the collection and description of foetuses can give clues about the organisms' mostly unknown early development. However, this type of biological material is extremely rare, limiting anatomical analysis due to the risk of damage or loss. Here, we describe the external and internal anatomy of an 84 cm long K. breviceps foetus. The methods utilised were non-intrusive, meaning that no incisions were made on the specimen. The foetus was analysed using computed tomography images and a three-dimensional reconstruction of the skeleton. A great number of features were observed, such as axial and appendicular skeletal structures, internal organs, echolocation apparatus and umbilical cord, as well as diagnostic characters of the species, such as the asymmetrical skull, spermaceti chamber and false gill pigmentation. We suggest that more specimens on different stages of development should be analysed by the same technique, as well as further comparison with specimens from other taxa, in order to facilitate more comparative studies on embryonic and foetal development of cetaceans.