544 MALE ORGANS OF GENERATION. [CHAP.XXXVU. 



beneath it are Cowper's glands. This part of the urethra com- 

 mences at the anterior extremity of the prostate, and terminates in 

 the bulbous portion. Its upper surface is rather longer than the 

 lower one, and it curves upwards. 



In the evacuation of the bladder, it is most likely that the 

 compressor urethra muscle, which contains striped fibre, and 

 guards the membranous portion of the urethra, becomes re- 

 laxed; then follows the relaxation of the sphincter vesicae, and 

 the contraction of the fibres of the bladder (detrusor urinae), 

 which causes the urine to escape from the urethra with consider- 

 able force. 



The spongy portion of the urethra is about six inches in length, 

 and is so called, because it is surrounded by the corpus spongiosum 

 urethrae. That part of the canal in the bulb is somewhat dilated, 

 but the diameter of the greater part of this portion of the canal is 

 uniform. Cowper's glands open near the anterior extremity of the 

 bulbous portion. When it reaches the glans, however, it undergoes 

 another dilatation, the fossa navicularis. At its orifice, the urethra 

 is contracted. 



Mucous Membrane. The short papillae covering the glans become 

 much elongated at the orifice of the urethra, and highly vascular 

 papillae are found in the anterior half of the fossa navicularis (fossa 

 Morgagnii), They then cease abruptly, but re-commence in the 

 posterior part of the glans, and are continued as far as the bulbous 

 portion. 



About one-third of an inch from the meatus, on the dorsal aspect 

 of the fossa navicularis, is situated the lacuna magna. In other 

 parts of the mucous membrane of the urethra, except in the pros- 

 tatic portion, are numerous small lacunae. 



Glands of Littre. The majority of these are simple involutions 

 of the mucous membrane, or lacunae ; but some may be described 

 as small branched glands or follicles, which are numerous in the 

 cavernous portion of the urethra. These become more simple in 

 the prostatic portion, and take the form of simple follicles. 



The epithelium lining the urethra and the small glands just re- 

 ferred to, is for the most part of the columnar form. 



Glandulce Tysoniance. These little glands are situated in the fold 

 of skin round the glans penis. They are modified sebaceous glands, 

 and the follicles of which they are composed, contain epithelium 

 and fatty matter, resembling that which is met with in the ordi- 

 nary sebaceous follicles of the skin. In this locality, these glan 

 open upon the soft skin of the prepuce, and are not associated wi 



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