394 



RODENTIA. 



likewise the terminations of the two vasa defe- 

 rentia. 



In the lagomys (Lcpus pusillus, ogotomis, 

 and afpinus^Pall) the vesiculae seminales are 

 double and separate. 



In the common squirrel each seminal vesicle 

 consists of a short canal folded upon itself. 

 This approximates its fellow on the opposite 

 side between the prostate and the canal of the 

 urethra ; and, contrary to what is usual in this 

 order, internal to the vasa deferentia. 



The prostate glands. The name of pro- 

 state gland is restricted by Cuvier to those 

 glandular masses of analogous structure to the 

 human prostate, the excretory canals of which 

 open by one or several orifices into the com- 

 mencement of the muscular portion of the 

 urethra, or into the first portion of that canal. 

 In some cases, however, the representatives of 

 the prostate are made up of numerous rami- 

 fied and complicated tubes, in which case they 

 are called tubular prostates. In the hare and 

 the rabbit, this gland is represented by the 

 glandular mass, which, as above described, forms 

 a portion of the walls of the vesiculre semi- 

 nales, and which extends for some distance 

 upon the muscular portion of the urethra 

 (f lg .28l.c). 



Fig. 283. 



Male organs of the Water Vole (Arvicola amphibius). 



a, glans penis ; c, the urinary bladder ; d, e, the 

 testicles ; /, g, epididymis, situated at some distance 

 from the testes ; k, I, vesiculas seminales ; m, n, o, p, 

 q, r, the prostates ; s, the rectum, the extremity of 

 which is surrounded by a glandular mass, t, from 

 which a milky fluid is poured into the rectum in 

 the vicinity of the anus, v. 



In the Alpine marmot it forms a consider- 

 able mass situated above the commencement 

 of the urethra, divided posteriorly into two 

 roundish lobes. 



In the squirrel the prostate gland is as long 

 as the muscular portion of the urethra, to 



which, however, it is only adherent at the two 

 points where its excretory ducts penetrate 

 that canal ; in this animal its shape is oval, 

 flattened above, and bilobed posteriorly. 



In the agouti the prostates (Jig.282. e,e) 

 assume the tubular form, each gland being 

 composed of a common trunk, divided into 

 branches and ramusculi, ending in vascular 

 enlargements. 



In the numerous family of rats, the pro- 

 states are represented by several packets of 

 ramified tubes, situated around the com- 

 mencement of the canal of the urethra. Two 

 others are connected with the inferior surface 

 of the vesiculae seminales : these consist of a 

 principal trunk, which has but few ramifica- 

 tions. These latter organs exist likewise in 

 the lagomys, and may perhaps be considered 

 accessory seminal vesicles. 



The Guinea-pig is furnished with numerous 

 ramified and convoluted tubes, connected to- 

 gether by a loose cellular tissue, which occupy 

 the situation of the prostate gland ofother 

 quadrupeds. 



Fig. 284. 







Generative organs of the male Beaver. 



a, opening common to the rectum and the urethral 

 canal; b, the prepuce; c, glans penis enclosed in 

 the prepuce ; d, body of the penis ; e, f, g, h, i, k, 

 preputial glands ; I, bifurcation of corpus caverno- 

 sum forming the bulb ; m, n, Cowper's glands ; o,p, 

 vesiculas seminales ; q, urinary bladder ; r, s, testicles ; 

 t, v, vasa deferentia. 



Cowper's glands. Most of the Rodentia 

 are provided with accessory glands, which, in 

 situation at least, correspond with those 

 called the glands of Cowper in the human 

 subject. 



In the male Agouti, these glands are two 

 round, flattened, and very vascular bodies 

 (Jig. 282. o), which open into the bulb of the 

 urethra by separate ducts (p). In the 

 Guinea-pig their structure is similar, as like- 



