1G4 MAMMALIA. 



to the muscles. There is not either an anterior crural, obturator, or sciatic nerve ; 

 there is a large one resembling the internal pudendal ; it arises in the male and female 

 from five nerves corresponding with the lumbar, and the lowest also forms the begin- 

 ning of the anterior caudal trunk ; it passes forwards, and in the male sends branches 

 underneath the pudic bone to the muscles connected with the penis ; one passes to the 

 muscles and skin connected with the anus ; others pass over the pudic bone to the 

 muscles of the penis ; a branch passes upwards towards the bladder, and its ramifica- 

 tions are joined by others from the hypogastric plexus, for the bladder and parts 

 connected with its neck; the pudic nerve then passes forwards on the penis, distri- 

 buting branches over its surface, some of which penetrate its tendinous parietes, whilst 

 one or two pass underneath the prepuce to terminate about the glans. In the female 

 a branch joins others from the hypogastric plexus for the bladder and vagina ; it then 

 forms two principal divisions : from the first, several are sent over the pudic bone to 

 the muscles and integuments of the vagina and its orifice, and one passes to the 

 mamma ; from the second division the largest branch passes upwards to the superior 

 angle of the orifice of the vagina, to be distributed about the clitoris, the smallest to 

 the muscles and integuments at the lower part of the vagina. Each caudal nerve on 

 passing out of the spinal canal gives a branch to the anterior and posterior caudal 

 trunk, which are of considerable size, for supplying the large muscles and integuments 

 of the anterior and posterior surface of the tail. The posterior caudal trunk has a 

 conjunction with seven superior sacral and lumbar nerves, which the anterior has not. 

 From each anterior caudal trunk branches pass anteriorly and laterally ; from the 

 posterior caudal nerve a branch passes obliquely towards each spinous process ; another 

 branch passes obliquely and then transversely in the direction of each transverse 

 process for supplying the muscles and skin. The anterior and posterior caudal trunks 

 become smaller as they reach the tail, and then divide for supplying respectively the 

 anterior and posterior flat surfaces. Although the animal lives in water, the large tail 

 is supplied by nerves arising at a very great distance above its extremity, and not from 

 nerves proceeding directly from the spinal cord, continued throughout the canal of 

 the caudal vertebrae, as in birds, amphibia, and fishes. The large nerves of the tail 



