PHILOSOPHY or ZOOLOGY. 



Besides these organs, there are others which appear to 

 be necessary towards perfecting the seminal fluid. These 

 are the Seminal Vesicles, the Prostate Gland, and Cowper's 

 Glands. The Seminal vesicles are two in number, corre- 

 sponding with the spermatic ducts *. In some cases their 

 cavity is simple, while in others it is divided into numerous 

 sacs, united together by cellular substance. The walls of 

 these vesicles are, in some animals, thin and simple, and 

 Jined with a continuation of the mucous membrane of the 

 urethra ; while in others they are thick and glandular, and 

 are evidently destined for secretion. These vesicles termi- 

 nate in the urethra, either by canals which are common to 

 the spermatic ducts, or by orifices peculiar to themselves, 



The seminal vesicles are wanting in many quadrupeds. 

 Their presence does not seem to be regulated by any uni- 

 form plan, or to be exhibited in any peculiar habits. Their 

 use, where they do exist, has not been satisfactorily deter- 

 mined. By some, they are considered to be receptacles of 

 the spermatic fluid ; while by others they are regarded as 

 destined to secrete a fluid peculiar to themselves. This 

 last opinion is rendered probable by the judicious remarks 

 of HUNTER -f, and confirmed by the whole history of their 

 structure, contents, and terminating canals. That they 

 are still connected with the reproductive system, is indicat- 

 ed by their increased size during the season of love. 



The Prostate Gland is situated at the commencement 



* The vesiculee accessories of CUVIER. are membranous tubes, varying in 

 number, adhering to the sternal side of the vesicles, or situated around the 

 Ixise of the urethra. They are filled with the same fluid as the vesicles, and 

 empty their contents into the urethra by a common duct, or by a separate 

 opening. They are very obvious in the mole and hedgehog. 



f- " Observations on certain parts of the Animal Economy." London? 

 J786, p. 27, 42. 



