DISCUSSION 441 



however, the condition found is that known as the " perforate clitoris ". In the Rodents 

 a urethral canal is formed by the ventral convergence of two flaps of the clitoric prepuce, 

 making a channel along the ventral side of the clitoris continuous with the urethra. In 

 the Insectivora and Prosimiae the clitoris itself is perforated by a urinary canal which 

 traverses the glans. In the Cetacea, however, the clitoris is not perforate and there is no 

 overlapping prepuce. There are indications of a short common urino-genital canal 

 in the foetus. In the adult the clitoris projects outside the vulva so that the two 

 openings — the urinary and the genital — become widely separated. In this respect it is 

 suggested that a derivation of the Cetacean condition from some groups of Insectivora 

 might be imagined such, for instance, as Tupaia where the urethral opening is situated 

 just within the vulva. In the mole the clitoris projects from the vulva but is perforated 

 by the urethra. In many Ungulates also a projecting clitoris is found but there is always 

 a urino-genital canal. 



(iii) The presence of a longitudinal fibrous band across the opening of the vagina 

 (the vaginal band). This has already been compared with the "hymen" of the mare 



(P- 394)- 



In the male system also an assemblage of primitive characters is found. 



(i) The form of the prostate. The prostata is not strictly speaking a prostate gland at 

 all, but a diffuse assemblage of urethral glands opening along the dorsum of the urino- 

 genital canal. This primary unlocalized condition of the glandulae urethrales is found, 

 as already stated, in Monotremes and Marsupials. 



(ii) The absence of accessory sexual glands. This is a character seen in many Insecti- 

 vores — a group, however, which shows within it many transitional stages, from com- 

 plete absence of one or other of these sets of glands to full development of all of them. 

 Cowper's glands are generally present in Insectivora. In some Carnivores they are 

 absent — notably the Arctoidea and Pinnipedia. The absence of anal glands is a feature 

 of the Ungulates. 



(iii) The intra-abdominal position of the testis has already been under discussion 

 (pp. 387, 388). It has been suggested that the testicondy of the Cetacea is secondary, but 

 possibly derived from an incomplete testicondy in which the testis originally descended 

 to a position in the posterior part of the abdominal cavity outside the inguinal ring. Such 

 a condition as this exists in the foetal ox before the full descent into the cremaster sac 

 takes place. It is suggested that a cremaster sac originally existed in the Cetacean fore- 

 runner in view of the occurrence of such a sac in Mesoplodon. Attention has been 

 drawn to the extremely primitive nature of the ligamentous attachments of the testis, 

 which take the form of a central ligament comparable to the ligamentum of the female 

 and of a plica diaphragmatica. It is the nature of these attachments which compels the 

 belief that the testes have never deserted their original position to the extent of a full 

 descent into a scrotum. 



(iv) It is assumed that the development of a two-horned uterus masculinus such as is 

 found in some Cetacea — particularly Mesoplodon — must be looked on as a primitive 

 character, representing a condition of " pseudo-hermaphroditism " further accentuated 



