4 io DISCOVERY REPORTS 



dactyles and Insectivores. In the latter group also there is a well-defined plica diaphrag- 



matica, but the presence of a peritoneal ovary sac constitutes an important difference 



from the Cetacea. 



The vascular supply 



The description already given for the male sex applies equally to the female. The 

 pudic artery passes through the vascular foramen of the rectus muscle and over the belly 

 of the ischio-cavernosus muscle near the median raphe (Fig. 12 j 3 ). It passes to the tip 

 of the clitoris, along the face of which it is turned towards the vulva and therefore 

 corresponds to the anterior face of the penis. A corresponding vein accompanies this 

 artery. Branches come off from the pudic arteries, accompanied by corresponding veins, 

 to the sides of the vulva and the ischio-cavernosus muscle. The ovarian arteries and veins 

 correspond in position with the spermatic veins of the male ; they enter the ovary at the 

 posterior end of the medianly directed hilus by which the ovary is attached to the 

 ligamentum latum. 



NERVES OF THE GENITAL REGION 



A stout lumbo-genital nerve (Fig. 20) is derived from the 10th, 1 ith and 12th lumbar 

 spinal nerves, and runs outwards and backwards towards the generative tract between 

 the deep and superficial parts of the hypaxial muscles. In the inguinal region this nerve 

 divides upon the inner surface of the rectus muscle and splits up, in the male, into a 

 number of branches to the prostata and to the muscles of the penis. A major branch 

 ascends upon the anterior face of the penis (Fig. 20 i) as a pudic nerve, accompanying 

 the arteries and veins of that name through the vascular foramen of the rectus muscle. 

 It becomes plexiform upon the shaft of the organ and enters the terminal cone. 

 There is also a branch from the point of origin of the pudic nerve running to the 

 rectum. In the female the neuro-vascular foramen of the rectus admits homologous 

 nerves to the vulva and the lower part of the vagina and a major branch to the clitoris. 

 The branch to the clitoris corresponds exactly to the pudic nerve of the male ; it passes 

 to the tip of the organ along its vulvar face, which is homologous with the anterior face 

 of the male penis. The rectal branch is also present in the female. Before passing through 

 the foramen of the rectus the genital nerve in both sexes sends backward a long stout 

 lumbar branch (Fig. 20^'), which accompanies a superficial lumbar vein and passes 

 outwards behind the pelvic bone and backwards towards the tail lateral to the ischio- 

 caudalis muscle. The hypogastric nerve (Fig. 20/) is given off from the lumbo-genital 

 nerve in front of the foramen of the rectus and passes forwards upon the ventral face 

 of the umbilicus. 



A large centrally placed hypogastric sympathetic ganglion (Fig. 20 //) is situated 

 dorsally upon the neck of the bladder, close to the point where the hypogastric arteries 

 ascend upon the umbilicus. It sends sympathetic nerves forwards on to the umbilicus, 

 and is connected with the 9th segmental sympathetic ganglion of each side by a single 

 nerve passing forwards and upwards to a small sympathetic ganglion dorsal to the 

 rectum (Fig. 20^). From this nerves run to the ovary and testis and forwards along 



