MALE GENITAL SYSTEM: INTERNAL ORGANS 



387 



Discussion of the position of the testis 

 Before closing the description of the testis and its ducts a little further attention must 

 be given to the abdominal position of the testis in the Cetacea — a condition commonly 

 known as "testicondy". All authors — notably Weber, Anthony and Meek — have 

 insisted that the testicondy of the Cetacea is secondary and that descent took place in 

 the Cetacean ancestor. 



Weber (1904), in his review of the question of the position of the testis among 

 Mammalia generally, distinguished two kinds of testicondy. 



(i) True testicondy. No inguinal canal exists and the ligamentum inguinale is 

 lacking. The testis retains its primitive dorsal position in the neighbourhood of the 

 kidney, slung by the "urinary ligament" which is a reduplication of the peritoneum 

 and carries the early mesonephros (epididymis) and the vasa deferentia. This forms the 

 plica diaphragmatica laterally. Such testicondy occurs in Monotremes, some Insecti- 

 vores, the elephant and Hyrax. In some Edentates (Bradypodidae and Myrmecopha- 

 gidae) the testes are pushed tailwards and lie be- 

 tween the bladder and the rectum. They are likewise 

 suspended in a urinary ligament. 



(ii) False testicondy. Here the ancestral descent 

 has been secondarily abandoned and the testes 

 lie in the abdominal cavity but have lost their 

 former dorsal position and now lie ventrally. The 

 inguinal canal is reduced in varying degrees and 

 only indicated at most. This condition is seen best 

 expressed in the Dasypodidae, where the testes lie 

 against the ventral body wall. Except in Chlamydo- 



phorus, a wide inguinal ring exists, through which 

 projects a small cremaster sac. Weber assigns the 

 Cetacea to this class. 



The arguments in favour of placing the Cetacea 



among the secondarily testicondal animals are based 



chiefly upon the ventral position of the testis and 



the existence of a genital cord attached to its pos- 

 terior end. Anthony (1922) argues further in favour 



of secondary testicondy from the fact that in Meso- 



plodon each testis is sunk in a recess of the abdominal 



cavity in the inguinal region, connected with the 



main abdominal cavity by a vagino-peritoneal canal. 



These recesses, Anthony believes, represent the 



vestiges of the cremaster sac. The same author 



also found muscle fibres arranged fan-wise in the 



testis ligament which he took to represent the vestiges of the cremaster muscle. The vas 



deferens in Mesoplodon (Fig. 7 A), after a convoluted part upon the testis takes a straight 



Fig. 7. Course of the vas deferens in: A. 

 Mesoplodon bidens (after Anthony — 1922). 

 B. Delphinus delphis (after Anthony — 

 1922). C. Balaenoptera physalns. (Major 

 sinuosities only.) 



a and b, Bends in the duct of Mesoplodon 

 and Delphinus believed by Anthony to be 

 homologous. 



