1004 



DR. C. F. SONNTAG ON THE PELVIC MUSCLES 



The sac of the tunica vaginalis is completely shut oft" from the 

 ahdoniinal cavity in the Chimpanzee and Man, In the Gibbon 

 and Orang the orifice remains open, but a ridge prevents the 

 testis passing to the abdomen in the latter (Milne-Edwards : 6). 

 The general charactei'S of the testis, particularly the size of the 

 corpus riighmorianum, are identical in the Chimpanzee and 

 Orang. Duvernoy (1) points out that the testis of the Gorilla is 

 small relatively to the size of the animal ; his illustration shows 

 that the epididymis has the same appearance as, but is relatively 

 larger than in the Chimjmnzee. 



lietzius (8) has made observations on the spermatozoa of the 

 Apes, and finds that those of the Gorilla resemble the human 

 spermatozoa most closely. 



The vas deferens is gradually formed by a narrowing of the 

 canal of the epididymis ; and it has the whip-cord consistence 



Text-figure 60. 



TAL. 



Transverse sections througli the testis of the Chimpanzee (A) and Gibbon (13). 

 The halves of the cut testis are folded outwards. Letters in text. 



which is usual. It lies in the posterior part of the thick sper- 

 matic cord. Its relations in the inguinal canal are as in Man. It 

 runs on the deep surface of the pelvic wall along a line corre- 

 sponding to the diameter of the acetabular cavity. Then it passes 

 between the bladder and the immense seminal vesicle of its own 

 side. At the level of the middle of the bladder the vasa deferentia 

 come together and run parallel to one another to the prostate. 

 They exhibit fusiform ampullary dilatations ; then they narrow 

 and pass into the prostate, where they unite into the common 

 ejaculatory ducts Avith the ducts of the seminal vesicles. In Man 

 and the Orang they receive the seminal ducts before they enter 

 the prostate. 



The seminal vesicles (text-fig. 61, V.S.) are two immense, pyri- 

 form bodies, whose narrow ends are directed downwards and 



