132 HUMAN EMBRYOLOGY AND MORPHOLOGY. 



ring. Arrest of descent is commonly a symptom of arrest of 

 testicular development. On the other hand, the testicle may 

 assume an ectopic position. The gubernaculum ends in the 

 scrotum principally, but bands of it pass to end on the root of 

 the penis, in the groin and in the perineum. These bands, 

 normally slight, may be big enough to influence the direction 

 of descent of the testicle ; hence cases occur in which the testis 

 is found in the groin, by the side of the penis or drawn back in 

 the perineum almost to the anus (Lockwood). 



The Mesorchium. — The testis and epididymis were suspended 

 within the abdomen by the common uro-genital mesentery. In 

 the course of the descent of the testis this becomes shortened and 

 binds the testis and epididymis firmly by their posterior borders 

 to the tunica vaginalis. Occasionally the uro-genital mesentery 

 and mesorchium persist ; the testicle is then liable to become 

 twisted and strangulated on its mesentery. I have seen three 

 such cases recently. The digital fossa is situated between the 

 mesorchium and mesentery of the Wolffian body. 



The meaning of the descent of the testes is unknown. In 

 many animals the testes descend only during the rutting season. 

 The inguinal canal, formed by the descent of the testis, is a source 

 of weakness in man (see p. 133). 



