[Temporal patterns of animal development]. / Izuchenie vremennýkh zakonomernostei razvitiia zhivotnykh.

A summary of studies on temporal characteristics of animal development performed during last 30 years using dimensionless unit as a parameter of development duration is presented. This approach allowed to introduce time as a parameter in comparative embryological studies. Thus the time of development became a subject of the embryological studies. Perspectives for the future work are defined.