THE MALE GENITAL ORGANS. 



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cavernosum. The latter is little developed, and presents, internally, a longitudinal fibrous 

 cord ; it is not much dilated during erection. In this act, the penis is elongated by the 

 straightening out of its curvatures, rather than by any real lengthening ; when erection 

 ceases, the organ is retracted into the preputial cavity by the contraction of the sus- 

 pensory cords, which reform its double inflection behind the scrotum. 



In the Earn and He-goat, the disposition of these parts is somewhat similar. (In the 

 former, the extremity of the urethra has the form of a narrow cylinder curved backwards, 

 its opening being a longitudinal slit. In Ruminants, towards the extremity of the sheath 

 are small teats; these, in the He-goat, are sometimes glandular, and secrete a fluid 

 analogous to milk.) 



Fig. 405. 



PENIS AND MUSCLES OF THE SHEATH OF THE BULL. 



1, Protractor muscle of the sheath ; 2, Retractor of ditto ; 3, Testicles in the scrotum ; 

 4, The 8 of the penis ; 5, Suspensory cords of the penis attached to the second 

 curve : 6, Subcutaneous abdominal vein. 



PIG. The testicles of this animal are round, and placed in the perineal region. The 

 scrotum is narrow, and but little detached: the pouches of which it is composed 

 appearing simply as two hemispherical prominences on the surface of the perineum. 

 There is nothing particular to be remarked in the epididymis and vas deferens ; (the 

 tail of the first is very voluminous; the latter has no pelvic dilatation.) 



The vesiculx seminales, with regard to disposition, are intermediate between those of 

 the Horse and Ox Their walls are thick and very glandular, and their interior is 

 diverticulated. (They are, proportionately, very large, and, in structure, closely re- 

 semble those of Ruminants ; indeed, in these animals they rather appear to be organs for 

 the secretion of a milky liquid that is mixed with the semen, than reservoirs for the 

 fecundating matter, as that fluid never contains any spermatozoa.) There are two 

 prostates: one disposed as in the Ox; the other placed across the neck of the bladder, 

 as in Solipeds. The penis resembles that of Ruminants, except in the absence of the 

 muscles of the sheath ; it has also a particular preputial sheath, which has been studied 

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