MALE ORGANS OF RODENTS. 



649 



of the base of the penis, inclosing the two bulbs with Cowper's 

 glands and their muscles, and terminates anteriorly in a strong 

 fascia above the dorsum penis, so as to compress against that part 

 the venae dorsales. In all Marsupials the penis is bent upon itself 

 ■ when passive and retracted ; with the glans concealed just within 

 the cToacal aperture, from which it emerges, as in oviparous Ver- 

 tebrates, when the penis is turgid and erect. 



§ 371. In Rodentia. — Here, likewise, the penis is habitually 

 retracted out of view, being strongly bent, in many (e. g. Sciurus, 

 Castor) in a sigmoid curve, with the glans directed backward, 

 fig. 497, 5, within a prepuce, which opens into, or forms part 

 of, the common passage, ib. g, e, a, in which the rectum, ib. b, 

 terminates. The testes undergo a periodical increase of size 

 and change of position, passing from the abdomen into a ses- 

 sile scrotum, and being again retracted, after the rut (except, 

 perhaps, in Leporidce) within the abdomen. Besides Cowperian 

 there are prostatic and vesi- 

 cular glands, usually large : 

 but, again, the Leporidce 

 show their exceptional cha- 

 racter in the Order by the 

 absence of the latter. In 

 the Hare (Lepus timidus) 

 the testes make a more con- 

 spicuous prominence than 

 in other Rodents, in their 

 scrotal bags, one on each side 

 the cloacal vent, fig. 505, a. 

 The tunica vaginalis retains 

 an opening wide enough for 

 the repassage of the testis 

 into the abdomen, but it 

 adheres to the bottom of the 

 sac, the serous membrane 

 of which is there reflected 

 by a fold upon the epididy- 

 mis, fig. 505, h, i, and be- 

 ginning of the vas deferens, ib. p, q. The testes, f, g, in this 

 figure, have been dissected from the scrotum and tunica vaginalis. 

 The epididymis is extended beyond the testis, as at h, i, before 

 being reduced and reflected as ( vas deferens : ' the sperm-ducts 

 enlarge at their termination between the urinary, e, and prctome- 

 tral, d, bladders, into the latter of which they open, very near 



Male organs, Hare. cxxn'. 



