Genifo-nrinary Ai^paratus of the Male Porpoise. 125 



ventral aspect. Each pelvic bone measured 7 "5 cm. in 

 length. Its caudal end was about 2'5 cm. in front of the 

 anal orifice, which in its turn was 38 cm. in front of the 

 mesial caudal notch. 



Posteriorly, each corpus cavernosum was somewhat 

 pointed, but it very abruptly expanded to form a bulb which 

 was situated immediately and entirely upon the ventral 

 aspect of the pelvic bone. As the two corpora cavernosa 

 approached each other mesially, they formed a ventral groove 

 or interval, which was occupied by the corpus spongiosum. 

 Towards the anterior ends of the pelvic bones the two 

 corpora cavernosa became reduced in size, and lying parallel 

 to each other, they thus formed the body of the penis, which 

 extended forwards in the ventral mesial line, separated from 

 the prostate gland by the strong interpubic membrane. In 

 front of the pelvic bones, the penis lay to the left side of the 

 mesial plane, and in this position it described a circle (7 cm. 

 in diameter), which carried it dorsally across the mesial 

 plane to the right side. Thereafter it passed backwards 

 until it abutted against the front end of the bulb of the 

 right corpus cavernosum, which was indented by the 

 pressure. After describing this complete circle, the penis 

 again passed forwards and occupied its groove upon the 

 ventral aspect of the abdominal wall in its course towards 

 the preputial sheath, within which the corpora cavernosa 

 began to dwindle in size, at a point about four inches 

 (10 cm.) from the end of the penis. They continued to 

 present erectile tissue, visible on section to the unaided eye, 

 to within three-quarters of an inch (2 cm.) of the tip of the 

 penis. After the erectile tissue was no longer distinguish- 

 able, the strong fibrous tissue of the corpora cavernosa 

 remained as an attenuated cylindrical rod similar to a crow- 

 quill in proportions, and extending to the tip of the penis. 



The corpus spongiosum adapted itself to the circular 

 course followed by the body of the penis, maintaining at the 

 same time its original relative position to the corpora caver- 

 nosa, although not always remaining strictly ventral in 

 position. Subsequent to the approximation of the two 

 corpora cavernosa they fused, and all superficial evidence 



