The _oviduct_, Fig. 54, f, which at this stage is, of course, of small diameter, extends across the ventral surface of its corresponding kidney and opens, f¹, into the posterior part of the cloaca as has already been described. Its peritoneal opening is some distance cephalad to the head of the ovary. Its course from this opening is straight until about the anterior end of the ovary; it then becomes somewhat convoluted for a short distance, but gradually straightens out, to pass to its posterior end as a nearly straight duct. The anterior straight portion of the oviduct is connected with the head of the ovary by a narrow band of mesentery. Each _testis_, Fig. 55, b, like the ovary, lies along the ventro-mesial border of its corresponding kidney and is connected with the posterior region of the cloaca by a slender vas deferens, Fig. 55, c, f. According to Rathke (in _C. acutus_) a small, slender epididymis lies along the outer side of the posterior half of each testis. _The Copulatory Organs._ The _penis_, Fig. 56, usually lies completely hidden in the cloaca; with its glans projecting backwards it is strongly arched; along the convex side of the arch, which is directed towards the upper wall of the cloaca, runs a groove, which serves as a penial urethra to conduct the semen. According to Rathke there may be recognized in connection with the penis two fibrous strands (resembling the corpora cavernosa of mammals), a corpus cavernosus urethrea, and a covering derived from the mucous membrane of the cloaca. The two fibrous strands arise from the pubis as two thick plates that soon completely fuse together by their adjacent sides to form the shaft, c, of the penis. These fused strands taper gradually towards the glans, in which they end in a point. From their mode of fusion there is left between them, on the side towards the upper wall of the cloaca, a fairly deep furrow that extends to the tip. According to Rathke these shafts are not of cavernous tissue, but the tube is lined by a layer of this tissue. [Illustration: FIG. 55. MALE UROGENITAL APPARATUS OF ALLIGATOR LUCIUS. (After Bronn.) _a_, kidney; _b_, testis; _c_, vas deferens; _d_, ureter; _e_, opening of the ureter into the cloaca; _f_, opening of the vas deferens into the cloaca; _g_, upper region of the cloaca; _h_, hinder region of the cloaca; _i_, rectum.] [Illustration: FIG. 56. MALE ORGAN OF ALLIGATOR LUCIUS, XI. (From Bronn, after Rathke.) _a_, the right crus penis; _b_, the mucous membrane of the cloaca that covers the organ; _c_, shaft of the penis; _d_, base of glans; _e_, point of glans; _f_, part of the ring muscle of the cloaca.]