676 DR. WATSON ON CHLAMYDOPHORTJS TRUNCATUS [Julie 18, 



urethra. As Professor Macalister observes, the vasa are not convo- 

 luted, neither do they present any trace of lateral diverticula or vesi- 

 culse seminales. 



Prostate gland is well developed, and forms a quadrilateral mass 

 of lobulated glandular tissue lying upon the upper surface of the intra- 

 pelvic urethra. It measures \ of an inch in length, and the same 

 in breadth, and is attached by its posterior border to the urethra, 

 its anterior border, which is free, extending between the vesical 

 openings of the ureters. The vasa deferentia sink into the latter 

 in their course to the urethra. Prof. Macalister does not refer to 

 this gland. 



Cowper's glands. — These, which are not mentioned by Macalister, 

 are two in number. Each lies in close relation to, and slightly under 

 cover of, the inner side of the cms penis. They are regularly pyri- 

 form ; and each measurss ^ of an inch in length. Their ducts pass 

 forward, and open at once into the commencement of the spongy 

 portion of the urethra. 



Penis. — The penis is formed by the junction of the two crura 

 exclusively, the third element or corpus spongiosum being entirely 

 absent. The crus penis of each side is attached to the ramus of the 

 ischium, as well as to the posterior half of the free border of the pubic 

 bone, the latter bone not uniting with its fellow of the opposite side. 

 Each measures ^ an inch in length, and lies along the inner side of 

 the adductor muscle of the thigh. The two crura unite opposite 

 the anterior border of the pubic bones, and together form, as it 

 were, a bridge, underneath which the rectum passes backward to the 

 anus. In consequence of the absence of a corpus spongiosum, the 

 penis is devoid of both bulb and glans. The penis itself measures 

 -J- of an inch in length, of which the basal -| are concealed by the inte- 

 gument, the remainder being free. 



Muscles of penis. — Of these there are three on each side of the 

 middle line : — (1) The ischio-cavernosus is strong and covers the 

 crus. Its fibres are attached posteriorly to the ischium, whilst ante- 

 riorly they are inserted into the crus behind the junction of the 

 latter with its fellow. A small portion of the crus between this and 

 the next muscle is uncovered by muscular fibres. (2) Bulbo-caver- 

 nosi. These two muscles are apparently continuous across the middle 

 line, and together form an investment of transversely arranged mus- 

 cular fibres which covers the lower surface of the basal portion of 

 the penis. No median raphe could be distinguished between them. 

 (3) Retractores penis. These are placed on the dorsal aspect of the 

 organ. Each is a delicate riband-like muscle which, arising from 

 the upper wall of the pelvic cavity, crosses the outer side of the de- 

 pressor caudse muscle, and passing down parallel to the crus penis, 

 and along the dorsal aspect of that organ, is inserted into the corpus 

 cavernosum immediately behind the tip of the penis. These muscles 

 doubtless act in the same manner as in Basypus, and serve to retract 

 the penis within the rudimentary prepuce. Beyond the statement 

 that the crus penis is invested by muscular fibres, Prof. Macalister 

 gives no account of the muscles just described. 



