ULTRASTRUCTURE OF EGG ENVELOPES AND EARLY EMBRYOS OF ROHDELLA AMAZONICA (TREMATODA: ASPIDOGASTREA) PARASITIC IN BANDED PUFFER FISH, COLOMESUS PSITTACUS.

Egg structure and early embryonic development of the aspidogastrean, Rohdella amazonica, a basal trematode, were studied by transmission electron microscopy (TEM) to gain insight into functional, developmental, and phylogenetic characteristics. Gravid worms were removed from the intestine of naturally infected banded puffer fish Colomesus psittacus, collected from the Bay of Marajó, Paracauari River (Pará, Brazil) and processed by standard TEM methods. By the time of pronuclear fusion, the fertilized zygote was already enclosed in a thick, electron-dense pre-operculate eggshell and an underlying layer of vitellocytes that fused into a vitelline syncytium as they were still secreting their shell granules. When cleavage commenced, a small number of macromeres moved to the area just underneath the eggshell, where they fused to form a single syncytial embryonic envelope. Simultaneously, the smaller blastomeres continued to divide as they maintained contact with each other, but remained separate from the vitelline syncytium. Concurrent with these cellular changes, a thickened knob expanded at one pole of the eggshell and began to form an opercular suture. By the time the operculum was fully formed, the vitelline syncytium had mostly degenerated, while the smaller blastomeres had become cohesive as a single mass that preceded the differentiation and morphogenesis of the cotylocidium larva. The general pattern of cleavage and eggshell formation resembles that of other trematodes and polylecithal cestodes, but the single embryonic envelope has been reported only in a few basal taxa. The only other aspidogastrean studied in detail to date is very similar, indicating close phylogenetic affinity and conservatism within this basal neodermatan and neoophoran group.

ULTRASTRUCTURE AND CYTOCHEMISTRY OF LATE EMBRYOS AND COTYLOCIDIUM LARVAE OF ROHDELLA AMAZONICA (TREMATODA: ASPIDOGASTREA), FROM THE TROPICAL ESTUARINE FISH, COLOMESUS PSITTACUS.

Developmental ultrastructure of late embryos and cotylocidium larval morphogenesis of Rohdella amazonica, an aspidogastrean parasite of fish, were studied to reveal the functional aspects of larvigenesis within the egg as well as phylogenetically relevant characteristics of the embryos and larvae in this basal trematode group. Gravid worms were removed from the intestine of naturally infected banded puffer fish Colomesus psittacus, collected from the Bay of Marajó, Paracauari River (Pará, Brazil) and processed by standard methods of transmission electron microscopy (TEM) and cytochemistry. During late cleavage and rearrangement of the blastomeres, the vitelline syncytium that plays a role in eggshell formation and nutrient provision to the embryo completes its apoptotic degeneration as the embryonic mass grows substantially. Early larval morphogenesis involves cellular positioning that defines the anteroposterior polarity of the differentiating larva. Progressing through larvigenesis, the anterior end forms a muscular oral sucker surrounding the mouth, which leads inward into the pharynx and expanding digestive cavity. At the posterior end, a large disc forms as a precursor to the eventual ventral disc. The fully formed cotylocidium, still within the eggshell, is flexed ventrally, bringing the 2 poles into near juxtaposition. The neodermatan tegument with outwardly projecting small microvilli becomes fully formed, as myocytons, a protonephridial system, and 2 glandular regions occupy the body's interior. The ultrastructural features described here are very similar to those reported for Aspidogaster limacoides from fish and somewhat similar to those reported for Cotylogaster occidentalis from molluscs, but differ from the more diverse larvae of neodermatan taxa that have been studied more extensively.

Sloths (Bradypus variegatus) as a polygastric mammal.

Fermentative herbivorous animals have peculiar conformations of the digestive system. It is known that B. variegatus obtained the capacity for evolutionary adaptation, due to their ecology and eating habits. However, despite the literature on feeding management for this species, there is a lack of published information regarding its gastric morphology, and such information would support a better understanding on the diet and digestion of these individuals. We found seven gastric compartments, which histologically revealed three distinct patterns: an aglandular keratinized fraction (mechanical stomach) and two glandular fractions, one a mucus secretor and the other one composed of acid secreting cells (chemical stomach). With these evidences we understand that these individuals have gastric resemblance to ruminants, with some inherent peculiarities of this species, including the transit of the bolus.

First record of Spirocamallanus krameri (Nematoda: Camallanidae) in Brazil: Morphological review.

This study aimed to describe the occurrence, morphology and prevalence of Spirocamallanus krameri, a parasite of Hoplerythrinus unitaeniatus collected in state of Pará, Brazil. The morphological and morphometric characteristics are consistent with the species S. krameri, by having a hexagonal mouth opening, 16 cephalic papillae and two lateral papillae on the amphids. The buccal capsule is internally different in both sexes, with (11-13) spiral ridges in males and (13-17) spiral ridges in females. The basal ring is well developed, and three teeth are present in males and absent in females. Ten sessile caudal papillae and a pair of phasmidial pores occur in males. The spicules are small, subequal, 81-101 µm in length and the tail is tapered. The vulva in females is postequatorial, the tail is conical with lateral phasmidial pores. Among the species of Spirocamallanus that have short spicules, the general morphology of S. krameri most resembles that of S. inopinatus, but differs from that species, which have two cephalic teeth visible (absent in S. krameri) and specimens of S. inopinatus do not have sexual dimorphism in the buccal capsule of present in S. krameri.

Sperm characters in the Hemiuridae (Digenea): first data on Aphanurus stossichii (Aphanurinae) and Ectenurus lepidus (Dinurinae).

The present work provides the first ultrastructural analysis of spermatozoa of two digeneans (Aphanurus stossichii (Monticelli, 1891) and Ectenurus lepidus Looss, 1907) belonging to the unexplored subfamilies of the Hemiuridae, namely, the Aphanurinae and the Dinurinae. In March 2019, these hemiurids were collected respectively from the digestive tract of the bogue Boops boops (Teleostei, Sparidae) and the Atlantic horse mackerel Trachurus trachurus (Teleostei, Carangidae) captured in the coastal zone of the Mediterranean Sea, off La Chebba (Tunisia). The ultrastructural study reveals that both spermatozoa exhibit the Bakhoum et al.'s type II of the digenean sperm cells characterized by the presence of two 9+'1' axonemes, an external ornamentation of the plasma membrane not associated with cortical microtubules and located in the anterior part of the spermatozoon, a single bundle of cortical microtubules, the maximum number of cortical microtubules located in a middle part of the sperm cell, and one mitochondrion. Moreover, they share several ultrastructural features with the studied spermatozoa of Hemiuridae such as the presence of two axonemes with the 9+'1' trepaxonematan pattern, a reduced number of parallel cortical microtubules organized into one field with their maximum number located in the median (A. stossichii) or posterior (E. lepidus) part of the spermatozoon, an external ornamentation of the plasma membrane in the anterior part of the spermatozoon, one mitochondrion, a nucleus, and a small amount of glycogen granules. However, the two studied hemiurids could be distinguished by the morphology of the anterior and posterior spermatozoon extremities and the presence of mitochondrial matrix granules in A. stossichii.

Anatomical, Histological, and Histochemical Analyses of the Scent Glands of the Scorpion Mud Turtle (Kinosternon scorpioides scorpioides).

Fossil evidence suggests that scent glands are basal features of Testudines. However, we know little about the structure of these glands in the Brazilian Kinosternidae. In this study, we described the macroscopic anatomy, histology, and histochemistry of the scent glands of three males and three females of Kinosternon scorpioides scorpioides from the Marajó mesoregion, Pará State, Brazil. In all of the specimens analyzed, regardless of sex, we found four scent glands, including two axillary and two inguinal glands that were structurally similar to each other. Each gland consisted of a single holocrine secretory lobule, a large lumen surrounded by relatively thin glandular secretory epithelium, an adjacent narrow layer of loose connective tissue, and a thick layer of skeletal striated muscle tissue surrounded by a serous tunic. The secretory epithelium produced a characteristic malodorous yellowish substance that was passed via a single duct through a bone channel in the bridge connecting the carapace to the plastron and excreted through an outer pore in the plate of each respective gland. Histologically, the secretory epithelium presented cells with two types of secretory vacuoles. Type 1 vacuoles stained red were the largest and most frequently found, and stained positively with Periodic acid-Schiff (PAS), suggesting they contained glycoproteic complexes. Type 2 vacuoles were translucent, smaller in size and fewer in number, and negative for PAS staining. Because they are very primitive structures, scent glands must play important roles in the lives of chelonians, but their real function remains unknown. Several hypotheses suggest that they can act as protection against ectoparasites, as a repellent of predators, in addition to attracting mates and eliciting other pheromonal responses. In this study, all animals reacted by exuding malodorous substances when handled, as a form of defense. However, these are just assumptions that need to be clarified with additional studies on animal behavior. Anat Rec, 303:1489-1500, 2020. © 2019 American Association for Anatomy.

Sperm characters of the aspidogastrean Rohdella amazonica (Aspidogastridae, Rohdellinae), a parasite of the banded puffer fish Colomesus psittacus.

The ultrastructural characteristics of the mature spermatozoon of the aspidogastrean Rohdella amazonica (Aspidogastridae, Rohdellinae) were studied by means of transmission electron microscopy. The sperm cell shows two axonemes of the 9 + '1' trepaxonematan pattern of Platyhelminthes, parallel cortical microtubules, a well-developed lateral expansion, external ornamentation of the plasma membrane, one mitochondrion, an electron-dense ring, a nucleus and granules of glycogen. The present results were compared with those observed in the aspidogastreans studied to date and in other Platyhelminthes. The lateral expansion and the electron-dense ring are typical characters for aspidogastreans. Although a lateral expansion has been described in other Platyhelminthes such as monogeneans and digeneans, the Aspidogastrea shows a much larger lateral expansion with both peripheral and internal microtubules. The dense ring is observed as a cylinder in a longitudinal view and shows a more granular appearance in sperm cells from the seminal vesicle in comparison to a more electron-dense appearance in sperm cells from the seminal uterine receptacle.

Morphological description of smell glands in Cyclopes didactylus.

A macroscopic and microscopic study of the mandibular organ of the silky anteater (Cyclopes didactylus) was carried out. The organ extends from below the zygomatic bone line to the middle of the mandible body, between the skin and the masseter muscle, on both sides of the animal. It has an average length of 11.7 mm and a width of 6.3 mm. In the mesoscopic analysis, it was observed that the organ presents in yellowish color due to the high amount of sebaceous content. In the histological analysis, the mandibular organ was observed to be composed of innumerable alveoli of the specialized sebaceous gland, surrounded by a layer of adventitia tunica. Scanning electron microscopy (SEM), revealed an apparent alveolar division with what appeared to be a sulcus at its center. The information here presented regarding the constitution and location of this structure has not been previously explored for other species and differs with respect to other descriptions for anteaters. Based on the present study, it is suggested that the mandibular organ is involved in social interaction in this species.

Morphology and Phylogeny of Calyptospora paranaidji n. sp. (Eimeriorina: Calyptosporidae), an Apicomplexan Parasite of the Hepatic Tissue of Cichla piquiti Kullander & Ferreira, 2006, From a Reservoir in the Brazilian Amazon Region.

The coccidians of the family Calyptosporidae are parasites of the tissue and organs of fish and aquatic invertebrates, in particular in the tropical region. In contrast with other apicomplexans of the suborder Eimeriorina, the diversity and ecology of the species of the genus Calyptospora have been poorly investigated, resulting in a lacuna that restricts the understanding of the distribution and prevalence of this group of eukaryote microparasites in the Amazon region. In the present study, the integrated comparative analysis of morphological characteristics, histological and structural traits, and the sequences of a fragment of the 18S rRNA gene, provides support for the identification of a new species of Calyptospora, found parasitizing the hepatic tissue of the piscivorous blue peacock bass, Cichla piquiti, captured in the reservoir of the Estreito hydroelectric dam on the middle Tocantins River in northern Brazil. This new species was named Calyptospora paranaidji n. sp.

Morphology of the Diaphragm Muscle in Southern Tamandua (Tamandua tetradactyla) and its Importance in Cases of Traumatic Hernia.

The wall of the diaphragm can be affected by changes caused by physical trauma, allowing the passage of viscera between the abdominal cavity and thoracic cavity, thus reducing the space for pulmonary expansion, leading to the formation of hernia and possible death. Thus, we aimed to characterize, size and determine the topography of the diaphragmatic muscle in the Southern Tamandua, since clinical and surgical activities in wild animals have become a reality more and more present in veterinary medicine. We used six adult animals, x-rayed and dissected, followed by collection of fragments of muscular portions for histological analysis. Initially we observed that the animals presented 17 thoracic vertebrae, 3 lumbar vertebrae and 5 sacral vertebrae. The diaphragm was conformed by three segments: sternal, costal and right and left diaphragm pillar, with presence of tendinous centre that housed the passage of the caudal vena cava, called foramen of the caudal vena cava. Dorsally to the tendinous centre, already in the muscle portion, we located the esophageal and aortic hiatus. These findings, as well as the microscopic, were equivalent to that found in the general literature also, corroborating with descriptions already carried out in other mammals' diaphragms.

Morphological Characterization of Diaphragm in Common Squirrel Monkey (Saimiri sciureus)

ABSTRACT The wall of the diaphragm can be affected by congenital or acquired alterations which allow the passage of viscera between the abdominal and chest cavities, allowing the formation of a diaphragmatic hernia. We characterized morphology and performed biometrics of the diaphragm in the common squirrel monkey Saimiri sciureus. After fixation, muscle fragments were collected and processed for optical microscopy. In this species the diaphragm muscle is attached to the lung by phrenopericardial ligament. It is also connected to the liver via the coronary and falciform ligaments. The muscle is composed of three segments in total: 1) sternal; 2) costal, and 3) a segment consisting of right and left diaphragmatic pillars. The anatomical structures analyzed were similar to those reported for other mammals. Histological analysis revealed stable, organized muscle fibers with alternation of light and dark streaks, indicating transverse striation.

Morphological Characterization of Diaphragm in Common Squirrel Monkey (Saimiri sciureus).

The wall of the diaphragm can be affected by congenital or acquired alterations which allow the passage of viscera between the abdominal and chest cavities, allowing the formation of a diaphragmatic hernia. We characterized morphology and performed biometrics of the diaphragm in the common squirrel monkey Saimiri sciureus. After fixation, muscle fragments were collected and processed for optical microscopy. In this species the diaphragm muscle is attached to the lung by phrenopericardial ligament. It is also connected to the liver via the coronary and falciform ligaments. The muscle is composed of three segments in total: 1) sternal; 2) costal, and 3) a segment consisting of right and left diaphragmatic pillars. The anatomical structures analyzed were similar to those reported for other mammals. Histological analysis revealed stable, organized muscle fibers with alternation of light and dark streaks, indicating transverse striation.

Anatomia e histologia do trato urinário do macaco-prego (Sapajus apella) / Anatomy and histology of the urinary tract in the capuchin monkey (Sapajus apella

Sapajus apella é um primata do Novo Mundo de porte médio e com distribuição geográfica desde a América do Sul até a Argentina. São bons modelos para estudo e nos últimos anos vêm sendo amplamente utilizados para este fim. A destruição progressiva do habitat natural desses animais os tem levado a migrarem para outras regiões, tornando-os, assim, mais susceptíveis à caça predatória. A necessidade de preservação das espécies silvestres desperta interesse por um maior conhecimento anatômico e clínico para estes animais. O presente estudo teve como objetivo examinar e descrever os aspectos morfológicos, quanto a anatomia macroscópica e microscópica dos órgãos do sistema urinário de fêmeas da espécie Sapajus apella visando estender o conhecimento anatômico para esta espécie. Foram utilizadas quatro fêmeas, oriundas do Centro Nacional de Primatas de Ananindeua/PA. istema urinário de S. apella apresenta características similares a outros primatas tanto humanos quanto não humanos e aos animais domésticos. Os rins apresentaram aspectos macroscópicos semelhantes aos rins de humanos, mas com a mesma classificação de outros primatas não humanos e alguns animais domésticos. A bexiga assemelhou-se aos animais domésticos e aos primatas de maneira geral, humano e não humano. O mesmo ocorreu quando analisamos estes órgãos histologicamente.

Sapajus apella is a primate of the New World of midsize and with geographical distribution from South America to Argentina. Good models for the study and in recent years have been widely used for this purpose. The progressive destruction of the natural habitat of these animals has led to migrate to other regions, thus making them more susceptible to hunting predator. The need for the preservation of wild species arouses interest by a greater anatomic and clinical knowledge of these animals. The present study was aimed to examine and describe the morphological aspects, as far as the macroscopic and microscopic anatomy of the organs of the urinary system of female Sapajus apella aiming to extend the anatomical knowledge for this species. Four females were used, from the National Center of Primates in Ananindeua - PA. The urinary system of S. apella has similar characteristics to other primates both human and non-human and domestic animals. The kidneys showed macroscopic aspects similar to the kidneys of humans, but with the same classification of other non-human primates and some domestic animals. The bladder was similar to domestic animals and primates in general, human and non-human. The same occurred when we analyze these components histologically.

Morfologia e morfometria da traqueia da preguiça (bradypus variegatus): conhecimentos para procedimentos de emergência / Morphological and morphometric trachea sloth (bradypus variegatus): knowledge for emergency procedures

Por ser uma espécie pouco estudada, principalmente do ponto de vista morfológico, objetivou-se conhecer a anatomia da traqueia da preguiça (Bradypus variegatus) a fim de fornecer informações para facilitar a eleição de tubo endotraqueal adequado, máscara laríngea ou cânula de traqueostomia para anestesia e procedimentos de emergência, uma vez que a mesma revelou-se possuidora de uma morfologia especial. Foram investigados 11animais jovens de idades diferentes, sendo quatro machos e sete fêmeas, provenientes do Museu Emilio Goeldi e doados a UFRA. Os exemplares foram perfundidos via intramuscular com solução aquosa de formol a 10% para fins de conservação e posteriormente foram dissecados em nível cervico-torácico, por meio de mesoscopia, expondo-se desde a laringe até os brônquios principais direito e esquerdo ao nível do hilo pulmonar. As traqueias foram divididas em cinco regiões (região cervical, região da primeira flexura, região da segunda flexura, região da terceira flexura e região da carina) as quais foram mensuradas altura e largura, assim como o comprimento traqueal total e parte do material foi submetido à técnicas de rotina histológica. Macroscopicamente, destacou-se a presença de sinuosidades acentuadas em porção médio caudal, contemplando a carina. O comprimento médio traqueal foi de 14,6cm. Microscopicamente, a traqueia era constituída por placas separadas de cartilagem hialina constituindo cada anel, sendo revestido por epitélio estratificado ciliado. Apesar da traqueia da preguiça comum apresentar revestimento padrão encontrado na traqueia de outros animais, na literatura não há registros de outras espécies que tenham morfologia macroscópica nas condições descritas, o que nos leva a sugerir, quando necessário acesso para ventilação de emergência, a prática da IOT e não a de traqueostomia.

As the sloth (Bradypus variegatus) is a little studied species, especially from a morphological point of view, this research aimed to define the anatomy of its trachea. The information would facilitate the selection of a proper endotracheal tube, laryngeal mask or tracheostomy tube for anesthesia and emergency procedures, since it appeared to have a special morphology. Eleven young animals of different ages were investigated, four males and seven females, obtained from the Emilio Goeldi Museum and donated to UFRA. The specimens were infused intramuscularly with 10% aqueous formaldehyde for preservation and were later dissected at the cervico-thoracic level, by mesoscopia, exposing the area from the larynx to the right and left primary bronchi at the hilum. The tracheae were divided into five regions (cervical, first flexure, second flexure, third flexure, and carina) for which length and width were measured, as well as the total tracheal length. Sharp windings were seen in the middle caudal portion, including the carina. The average tracheal length was 14.6 cm. Microscopically, the trachea was made up of separate plates of hyaline cartilage forming each ring, lined with ciliated epithelium. Despite the trachea of the common sloth displaying the same lining pattern found in other animals, there are no reports in the literature of other species having a macroscopic morphology as described here, which leads us to suggest, where appropriate access to emergency ventilation, the practice of IOT and not tracheostomy.

A new species of Mesocoelium (Digenea: Mesocoeliidae) found in Rhinella marina (Amphibia: Bufonidae) from Brazilian Amazonia.

Mesocoelium lanfrediae sp. nov. (Digenea: Mesocoeliidae) inhabits the small intestine of Rhinella marina (Amphibia: Bufonidae) and is described here, with illustrations provided by light, scanning electron microscopy and molecular approachs. M. lanfrediae sp. nov. presents the typical characteristics of the genus, but is morphometrically and morphologically different from the species described previously. The main diagnostic characteristics of M. lanfrediae sp. nov. are (i) seven pairs of regularly-distributed spherical papillae on the oral sucker, (ii) ventral sucker outlined by four pairs of papillae distributed in a uniform pattern and interspersed with numerous spines, which are larger at the posterior margin and (iii) small, rounded tegumentary papillae around the opening of the oral sucker, which are morphologically different from those of the oral sucker itself, some of which are randomly disposed in the ventrolateral tegumentary region of the anterior third of the body. Addionally, based on SSU rDNA, a phylogenetic analysis including Brachycoeliidae and Mesocoeliidae taxa available on GenBank established the close relationship between M. lanfrediae sp. nov. and Mesocoelium sp.

A new species of Mesocoelium (Digenea: Mesocoeliidae) found in Rhinella marina (Amphibia: Bufonidae) from Brazilian Amazonia

Mesocoelium lanfrediae sp. nov. (Digenea: Mesocoeliidae) inhabits the small intestine of Rhinella marina (Amphibia: Bufonidae) and is described here, with illustrations provided by light, scanning electron microscopy and molecular approachs. M. lanfrediae sp. nov. presents the typical characteristics of the genus, but is morphometrically and morphologically different from the species described previously. The main diagnostic characteristics of M. lanfrediae sp. nov. are (i) seven pairs of regularly-distributed spherical papillae on the oral sucker, (ii) ventral sucker outlined by four pairs of papillae distributed in a uniform pattern and interspersed with numerous spines, which are larger at the posterior margin and (iii) small, rounded tegumentary papillae around the opening of the oral sucker, which are morphologically different from those of the oral sucker itself, some of which are randomly disposed in the ventrolateral tegumentary region of the anterior third of the body. Addionally, based on SSU rDNA, a phylogenetic analysis including Brachycoeliidae and Mesocoeliidae taxa available on GenBank established the close relationship between M. lanfrediae sp. nov. and Mesocoelium sp.

Morphological and molecular characterization of Ortleppascaris sp. larvae, parasites of the cane toad Rhinella marina from eastern Amazonia.

This study presents a new record for the occurrence of larval Ortleppascaris sp.(Sprent, 1978). The nematodes were collected from inside fibrous cysts found in the livers of cane toads, Rhinella marina (Linnaeus, 1758), captured in eastern Brazilian Amazonia. This is the first record of Ortleppascaris sp. larvae in both Brazil and this amphibian host, increasing its distribution in South America as well as expanding the number of helminths known to infect this toad. The detailed description of Ortleppascaris sp. provides new taxonomic data for these larvae, as well as sequences of the internal transcribed spacers and small subunit DNA segments, and the cytochrome oxidase I gene, which will, in time, contribute to a better understanding of the phylogeny of this group of parasites.

Liver histopathology in the cane toad, Rhinella marina (Amphibia: Bufonidae), induced by Ortleppascaris sp. larvae (Nematoda: Ascarididae).

Exposure to parasites is considered to be an important factor in the development of many diseases and histopathologies which are the result of the parasite-host interaction. The present study evaluated the impact of natural infection by larvae of Ortleppascaris sp. (Nematoda: Ascaridida) in the liver of the cane toad Rhinella marina (Linnaeus, 1758). Larvae were encysted in nodules delimited by collagenous fibers and fibroblasts or freely within the hepatic parenchyma, provoking a clear response from the host. The histological examination of the liver revealed viable larvae in a number of different developmental stages, as well as cysts filled with amorphous material and cell residues and surrounded by dense fibrotic tissue. The infection of the liver by these larvae induces a significant increase in the area occupied by melanomacrophages and a reduction or deficit in the vascularization of the liver, hypertrophy of the hepatocytes, vacuolar bodies, and cytoplasmatic granules. Focal concentrations of inflammatory infiltrates were observed enclosing the unencapsulated early-stage larvae. These results indicate that infection by Ortleppascaris sp. induces severe physiological problems and histopathological lesions in the liver of R. marina .

Morphological redescription of Dirofilaria immitis.

Morphological descriptions of Dirofilaria immitis are scarce. For this reason, we carried out morphological studies using both light and scanning electron microscopy for this filaroid species. Morphometric and morphological data were compatible with previous descriptions of D. immitis , but several anatomical structures are described by scanning electron microscopy for the first time, such as details of the cuticular striations, positioning of amphids, visualization of anal and vulvar opening, descriptions of deirids, lateral line, the pair of phasmids in the posterior end in females, and visualization of a small pair of latero-terminal papillae in the posterior end in males.