Observations on the Spermatogenic Cycle of the Grass Snake, Natrix natrix （Serpentes： Colubridae） in Northern Iran
摘要
The Grass Snake, Natrix natrix, is one of the non-venomous oviparous snakes of the family Colubridae, found in Mazandaran, a northern province of Iran. In order to study the spermatogenic cycle of this species in the area, sampling was done from April to November, and twenty-six male snakes were collected by hand during daylight hours. Testes were extracted from the specimens, and were fixed and prepared for histological examination. The results indicated that the spermatogenesis started in early June, reached its height in August and September, and ended in November. The mean body length of the specimens was measured 636.21 mm, and the mean volume of testes was 524.54 mm3and 569.06 mm3for the right and left ones, respectively, and the mean weight of the testes was 0.051 g. Spermatogenesis in this species is aestival and sperms are stored for use in the year following production.