THE MALE REPRODUCTIVE-SYSTEM AND THE PHYLOGENY OF ELEPHANT-SHREWS (MACROSCELIDEA)

Elephant-shrews show many unusual features of their reproductive syste ms. The testes lie in the abdominal cavity, just caudal to the kidneys , and are relatively very small. The epididymis is long and most sperm are stored in a coiled region, possibly homologous to the cauda epidi dymidis, adjacent to the rectum. Spermatogenesis occurs throughout the year but there are marked seasonal changes in the size of the testis and accessory glands. The spermatozoa have a spatulate-shaped nucleus with a long acrosome. The subacrosome is pointed or more rounded in Ma croscelides and Petrodromus but is anvil-shaped in Elephantulus with l ateral barbs. Coarse fibres 1, 5, 6 and 9 are enlarged but in E. edwar dii there is a great enlargement of all the coarse fibres. The accesso ry glands consist of five pairs of prostate glands, a uterus masculinu s and a pair of bulbourethral glands. The penis is very long and runs cranially under the abdominal skin. The distal end of the glans has a characteristic shape for each genus. Features of the male reproductive system give no support for the suggested relationship of elephant-shr ews with lagomorphs and rodents but do show some similarities with the paenungulates (hyrax, elephant and sireneans).