The urogenital organs in the young animal are so similar in the two sexes that one might easily be mistaken for the other; of course in sexually mature animals, especially during the breeding season, this is not the case.
The kidneys, [Fig. 54], k, [Fig. 55], a, are flattened, lobulated organs lying against the dorsal body wall. The large anterior lobe of each kidney is pointed at its anterior end and lies at some little distance from its fellow; it is partially divided into secondary lobes and is traversed on its ventral surface by branching blood-vessels. Its antero-medial border is sometimes partially concealed, in a ventral view, by the elongated gonad of that side. Caudad to the main lobe of the kidney is a smaller, usually distinct, lobe in contact mesially with its fellow of the opposite side.
A fairly wide ureter, [Fig. 54], u, [Fig. 55], d, extends from the posterior end of each kidney to open ([Fig. 54], u¹, [Fig. 55], e) into the anterior region of the cloaca, as described in connection with the digestive system.
The ovary, [Fig. 54], o, as noted above and as seen in [Figs. 54] and [55], in the young animal is of practically the same shape as the testis. The ova at this stage are of microscopic size and are hence not visible to the naked eye. The ovary, even at this stage, is more or less distinctly marked off into lobules by a series of small grooves.
Fig. 54. Female Urogenital System.
f, oviduct; f¹, opening of oviduct; k, kidney; m, mesentery; o, ovary; u, ureter; u¹, opening of ureter.
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.