xxxi.] THE MALE GENITAL ORGANS. 255 



cells, the outer portion of the cell being distinctly 

 striated (Langerhans). In the cell the reticulum is 

 also distinct. In this respect the alveoli completely 

 resemble those of the sub-maxillary of the dog, but 

 there are no real crescents in the alveoli of Cowper's 

 gland. 



339. (7) The corpus spong^osum. The cor- 

 pus spongiosum of the urethra is a continuation of 

 the rudimentary corpus cavernosum above-mentioned 

 in connection with the pars membranacea of the 

 urethra. It is essentially a plexus of large veins 

 arranged chiefly longitudinally and leading into small 

 efferent veins. Between the large veins are bundles 

 of non-striped muscular tissue. The capillary blood- 

 vessels of the mucous membrane of the urethra open 

 into the veins of the plexus. The outer portion of 

 the corpus spongiosum, including the bulbus urethrse, 

 shows, however, numerous venous sinuses, real caver- 

 rige, into which open capillary blood-vessels. 



340. The glaiis penis is of exactly the same 

 structure as the corpus spongiosum. The outer surface 

 is covered with a delicate fibrous tissue membrane, 

 which on its free surface bears minute papillae, 

 extending into the stratified pavement epithelium. At 

 the corona glandis exist small sebaceous follicles, the 

 glands of Tyson; they are continued from the inner 

 lamella of the prepuce, where they abound. The 

 papillae of the glans contain loops of capillary blood- 

 vessels. Plexuses of non-medullated nerve-fibres are 

 found underneath the epithelium of the surface of 

 the glans. With these are connected the end bulbs 

 described in a former chapter as the genital nerve-end 

 corpuscles. 



341. (8) The corpora cavernosa penis. Each 

 corpus cavernosum is enveloped in a fibrous capsule, 

 the albuginea, made up of lamellae of fibrous con- 

 nective tissue. Numerous Pacinian corpuscles are 



