Seasonal changes in testes and thumb pads of the toad, Bufo marinus (Linn.) and their correlation with fluctuations in the environmental factors.

In present studies, the slow rate of spermatogenetic activity and regressed condition of Leydig cells have been correlated with declining day length and ambient temperature during winter months (November--February). The gradual enhancement of the spermatogenetic activity and increase in the number and nuclear diameter of Leydig cells from March to June have been associated with increasing day length and ambient temperature. During July and August, the process of spermiation has been associated with the high ambient temperature as well as abrupt rise in the relative humidity following heavy rains in this period. A direct relationship has also been drawn between the activity of Leydig cells and the development of androgen-dependent thumb pads.