54 ZOOTOMY. 



is brought back from the tail, kidneys, genital organs, cloaca, rectum, 

 pelvic fins, &c. These veins run along the inner side of the kidneys 

 (see 130), and enter the sinus at about the anterior extremity of those 

 glands : leaving the sinus, the cardinal veins are continued forwards 

 and curve round the gullet to join the precaval sinus (pc.s) : they are 

 best seen at a future stage. 



XXIII. The following organs are also best observed at 

 this stage : 



no. In the male, the testes (Fig. 18, /), irregularly oval 

 bodies, closely connected with the venous sinus, one on 

 either side. In the adult they have a flat ventral and a 

 rounded dorsal surface : the former has a granular appear- 

 ance, the latter is beset with small rounded elevations. In 

 the young condition the whole surface is quite soft and 

 granular. At its anterior end, even in the adult, the testis 

 is soft and thin, and passes into the upper end of the 

 epididymis (see 114) by which its secretion is carried 

 off. 



in. In the female the ovaries (Fig. 19, ov] : these in 

 the young condition are indistinguishable from testes, but in 

 the adult state are covered with elevations varying from the 

 size of the yolk of a hen's egg downwards the Graafian 

 follicles. Note the absence of any duct in direct con- 

 nection with the ovary, the ova having to pass into the 

 peritoneal cavity before reaching the aperture of the ovi- 

 ducts. 



112. The fold of peritoneum called mesorchium in 

 the male, mesoarium in the female, by which the genital 

 glands are supported. 



XXIV. Remove the genital glands and the venous 

 sinus, and very carefully dissect away the perito- 

 neum from the organs still left in the abdominal 

 cavity, noting 



113. The kidneys (Figs. 18 and 19, k), flat, reddish 



