474 CETACEA. 



lobes of the glans, the canal has the outline of a small arch 0*06 inch across, 

 and an inch further on it is a minute obliquely transverse slit 1-05 inch, and, an 

 inch in advance of this, it is vertical and hardly distinguishable from the crypts 

 of the spongy body. At the base of the lobes of the glans it is a transverse opening 

 0*12 inch across, and tracing the canal into the filiform process its capacity is increased 

 to 0*24, in a specimen much shrunk by preservation in strong spirit. The mucous 

 surface of the urethra is thrown into finer longitudinal folds throughout its whole 

 length, from the membranous portion to the base of the glans ; thus conferring on it 

 a considerable capacity for distention. 



The only lacunae I detected occur opposite to the attachments of the retractor 

 muscles and are elongately crescentic openings directed backwards. 



In the female the urethra is 2*50 inches in length. Between the extremities of 

 the grooves of the ureters, which run backwards for 0'90 inch, a longitudinal fold 

 arises from a small eminence 0*25 inch long by 0*10 high and is prolonged along the 

 whole extent of the vertical wall of the canal. 



The prostate has not been demonstrated to my satisfaction, as the specimen 

 under examination is not in good preservation. Eour small pits arranged somewhat 

 in a circle and situated to the side of the caput gallinaginis appear to be the open- 

 ings of the ducts from this body. The caput gallinaginis will be considered in con- 

 nection with the vasa deferentia. 



Corpora cavernosa. — After separating from each other, each is prolonged back- 

 wards and outwards for 1*50 inch as a dense fibrous rod ; this when bisected longitu- 

 dinally is found to be filled with a soft spongy substance, contained in a special 

 cavity shut off by a fibrous interval of three-quarters of an inch from the true 

 cavernous substance of the penis. 



The corpus spongiosum investing the hinder wall of the urethra divides into 

 two crura ; each prolonged into the centre of the hulbo-cavernosus muscle of its 

 own side, and lodged in a strong fascia derived from the inner wall of the fibrous 

 investment of the corpus cavernosum in the erector muscle. A vertical section 

 shows this position of the spongy body extending 2*25 inches backwards from the 

 urethra, around which it is prolonged forwards as a thin investment. 



Belations of corpus cavernosum and corpus spongiosum. — Eight inches 

 anterior to the membranous portion, a transverse section shows the corpus ca- 

 vernosum with a rounded outline. Immediately behind the attachment of the 

 prepuce the section is transversely oval, and about halfway between the latter 

 locality and the base of the glans the organ preserves the same form. A section 

 through the base of the lobes of the glans demonstrates the spongy body of nearly 

 the same dimensions as the separated halves of the corpus cavernosum, between 

 and rather above which it is placed. The corpora cavernosa either terminate here 

 or are prolonged in their fibrous coverings into the lobes of the glans ; while the 

 spongy body, or more correctly the urethral continuation of it, is lengthened into the 

 filiform process with the urethra at its upper extremity. The corpora cavernosa 

 terminate in a rounded end 0*25 inch across, and external to their fibrous sheaths are 



