THE EFFECT OF ENVIRONMENTAL FACTORS ON THE SPERM CYCLE OF TRITURUS VIRIDESCENS

¹ Osborn Zoological Laboratory, Yale University, New Haven

1. The observations of Adams (1940) on the normal sperm cycle of Triturus viridescens were confirmed. An active period of gametogenesis following the spring breeding season results in the formation of mature sperm by September. Mature sperm are discharged in the fall but during winter the testes are inactive, consisting of spermatogonia, sperm, and evacuated cysts. Sperm discharge recurs in the spring.

2. At all periods of the cycle temperatures below 12° C. prevented spermatogenesis and sperm discharge and caused the degeneration of spermatocytes and spermatids. Temperatures above 12° C. induced spermatocyte formation in winter; 21°-25° C. in winter caused sperm discharge and in summer these temperatures allowed normal spermatogenesis.

3. Variations in light rations (constant light, increasing light, constant darkness) did not affect the cycle. Lack of food did not inhibit spermatogenesis.

4. It is concluded that temperature is the principal environmental agent influencing the sperm cycle of Triturus viridescens.