722 MAMMALIA. 



product of their secretion into the urethra by two ducts (Jig. 332, 

 B, c, c), quite distinct from the vasa defer entia. 



(852.) The prostates are the next succenturiate glands, super- 

 added to the essential generative organs of the placental Mam- 

 mals ; and so diverse is their structure in different tribes, that it 

 is not always easy to recognise them under the varied forms that 

 they assume. 



In Man the prostate is a solid glandular mass, that embraces 

 the commencement of the urethra, into which it discharges its 

 secretion by numerous small ducts ; and this is the most common 

 arrangement throughout the Mammiferous orders. 



In RUMINANTS, SOLIPEDS, and in the Elephant, there are 

 two or even four prostates of a very different kind ; each gland 

 having a central cavity, into which smaller cavities open by wide 

 orifices. In these creatures, therefore, the prostatic secretion accu- 

 mulates in the interior of the gland, from whence it is conveyed 

 into the urethra by appropriate excretory canals. 



In most of the RODE NT i A, in the Mole and in the Hedgehog, 

 the structure of the prostate is so peculiar, that many distinguished 

 comparative anatomists refuse to apply the same name to organs 

 that obviously represent the gland we are describing, preferring 

 with Cuvier to call them " accessory vesicles.' 1 '' 



In the Hedgehog, the prostate is replaced by two large masses 

 (Jig. 332, A, d, d), each composed of parallel, flexuous, and branch- 

 ed tubes, all of which unite into ducts common to the whole group, 

 whereby the fluid elaborated is conveyed into the urethra through 

 minute orifices (Jig. 332, B, e, e). 



(853.) A third set of auxiliary secreting bodies, very generally 

 met with, are called by the name of" Cowper's glands." These 

 in our own species are very small, not exceeding the size of a pea ; 

 but in many quadrupeds they are much more largely developed. 

 In the Hedgehog (Jig. 332, A,/) they are obviously composed of 

 convoluted tubes, and their ducts open by distinct apertures 

 (B, g, g) into the floor of the urethra. 



(854.) The canal of the urethra, through which the urine as well 

 as the generative secretions are expelled from the body of the male 

 Mammal, is a complete tube, and no longer a mere furrow, as we 

 have seen it to be in all the Ovipara possessed of an intromittent ap- 

 paratus. It extends from the neck of the bladder to the extremity 

 of the penis; but in this course, owing to its relations with the sur- 

 rounding parts, it will be necessary to consider it as divisible into two 



