Chromosome behaviour in the male ferret and mole during anoestrus

The breeding season of many Mammals is restricted to a relatively short period of the year. In such species usually both sexes exhibit a more or less well-defined seasonal variation in their reproductive organs. Several investigators have found that these variations in the male consist chiefly of alteration in the size of the testes and epididymis, accompanied by marked histological and cytological changes leading to a complete absence of sperms during the quiescent or anoestrous period. The cyclic histological changes in the testes and in the accessory organs have been described in detail in the ferret (Putorius furo, L .) by Allanson (1932), and in the mole (Talpa europea, L .) by Tandler and Grosz (1912) and Allanson (unpublished ). It was found in both genera that during the breeding season spermatogenesis is complete and very active in the rapidly growing testis, but after that period the reproductive organs return to a quiescent state and sperms are entirely absent.