126 



DESCENT OF THE TESTICLES. 



which grows simultaneously into the epithelium, and eventually cell-nests are sepa- 

 rated and included in the mesoblastic tissue. Whether these nests are derived from 

 the division of the primordial ova only, or whether they also include other cells of the 

 germinal epithelium is not clear. It would appear that from these cell-nests the 

 epithelium of the seminiferous tubules is developed, although all stages of the 

 process have not been observed. The cell-nests eventually become connected with 

 the outgrowths from the Wolffian bodies (fig. 153, st\ which as already mentioned, 



Fig. 13. -SECTION OF THE GERMINAL EPITHELIUM AND ADJACENT STROMA IN A MALE CHICK EMBRYO. 



(Semon. ) 



g. (p, germinal epithelium forming a thickened ridge-like projection ; pr.ov, primitive ova of various 

 sizes, some in the germinal epithelium and others somewhat beyond the limit of this epithelium ; st, 

 strands of cells which have grown from the Wolffian body towards the germinal epithelium, and one of 

 which appears connected with an enlarged primitive ovum. 



form the rete testis and the efferent tubes of the testicle. The reproductive gland is 

 in both sexes at first attached directly to the Wolffian body (fig. 156, A, ot), which 

 itself is attached by a fold of peritoneum to the back of the abdominal cavity. 

 This fold becomes the mesovarium or mesorchium as the case may be. A band also 

 passes from the Wolffian body upwards to the diaphragm, and another fold contain- 

 ing involuntary muscular fibres the plica giibernalrix runs down towards the 

 groin from the lower part of the Wolffian body and the duct. This band, as the 

 Wolffian body becomes atrophied, is found to be attached to the reproductive organ, 

 constituting the yubernaculitm testis in the male, and the round ligament of the ovary 

 in the female (fig. 15G, g\ 



Descent of the Testicles. The testicles originally lie in the lumbar region of 

 the abdomen. From this part they become shifted, at first to the intestinal 

 abdominal ring, opposite which they are found in the sixth month, and which they 

 enter in the seventh month, then down the inguinal canal into the scrotum, which 



