THE MALE OKGANS OF GENERATION. 225 



situated along the dorsum of the organ, and communicate with 

 the lymph-glands in the pelvis and those of the groin. 



The nerves and their terminations in the penis are derived 

 from the cerebro- spinal and sympathetic systems. In the loose 

 tissue external to the tunica albuginea large medullated fibres 

 are observed ; these give off smaller branches which enter the 

 cavernous structure, and may be followed for some distance as 

 medullated or non -medullated fibres. In this same tissue are 

 found, at the root, shaft, and vicinity of the corona glandis, 

 Pacinian corpuscles. They are oval in shape, and have their 

 long diameter parallel to the long axis of the penis. These 

 bodies have also been met with in the cavernous structure. 

 The glans is especially rich in nervous elements, and here are 

 found bodies known as the "genital nerve-corpuscles" situated 

 in the tissue of the mucous membrane at the base of the papil- 

 lae. These bodies are round in shape, vary in size from 0.1439 

 to 0.2001 mm. in diameter, and have characteristic constrictions 

 upon their surface, giving them a mulberry-like appearance. 

 The ordinary terminal bulbs of Krause are also met with in 

 this location. 



The urethra of the male serves as the excretory canal for 

 the urine and seminal fluid. An anatomical division is made 

 into the prostatic, membranous, and spongy parts. The canal 

 is lined with a mucous membrane, external to which there is a 

 fibrous layer rich in elastic fibres, having a cavernous struc- 

 ture ; external again to this is the muscular coat, composed of 

 involuntary muscular fibres arranged in two layers, an internal, 

 or longitudinal, and an external, or circular. There are also 

 numerous fasciculi of oblique fibres, which serve to connect the 

 two layers. 



The histological structure and arrangement of the three 

 parts of the urethra are unlike, and must be separately 

 studied, (a) In the prostatic portion the mucous membrane 

 lies in longitudinal folds. A laminated epithelium covers the 

 inferior wall, while the sides and superior wall are lined with 

 a transitional variety. The prominence of this portion of the 

 urethra, the colliculus seminalis, is composed of elastic tissue 

 and smooth muscular cells, which form a cavernous structure. 

 Throughout this spongy tissue, near the surface, are seen 

 glands similar to those found in the prostate. Racemose glands 

 (Littre's glands), imperfectly developed, lined with cylindrical 



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