THE MALE ORGANS OF GENERATION. 233 



which fact is held to indicate active proliferation. These bodies 

 are termed seminal cells, and in the embryo are said to possess 

 contractility and amoaboid movement. 



The seminiferous tubules upon entering the corpus High- 

 mori lose their special external coat, which blends with the 

 connective tissue of this region. Their epithelial lining con- 

 sists of cylindrical cells with short cilia. After* leaving tho 

 corpus Highmori and increasing in size, they have an additional 

 coat of smooth muscular fibres, which, further down in the 

 body of the epididymis, consists of two layers, an internal and 

 an external or longitudinal coat. The epithelium lining the 

 canal of the epididymis is composed of cells with long, oval 

 nuclei, and provided with long tufts of cilia. Indeed, the lar- 

 gest cilia found in the human body are upon the large cylindri- 

 cal cells, which cover the upper part of the canal of the epi- 

 didymis. Beneath this layer of ciliated bodies is a second of 

 small, polyhedral ones Vvith round nuclei. 



The vas deferens, which may be considered as analogous 

 in many respects to the excretory duct of a glandular organ, 

 is made up of an external or fibrous coat, a middle or mus- 

 cular, and a mucous membrane, which is located most inter- 

 nally. Covering this membrane are epithelial .elements which 

 differ in the various parts of the duct. At the beginning there 

 is a single layer of cylindrical cells, between which, sometimes, 

 there are spindle-shaped bodies ; the former possess delicate 

 cilia. At about four centimetres from the epididymis the cilia 

 are lost, but the character of the cells remains the same, ex- 

 cept that a striated border can be seen in many. In children, 

 a difference exists between the extra- and intra-abdominal por- 

 tions of the duct. The former, or extra, is lined by a lami- 

 nated epithelium, composed of a superficial layer of short 

 cylindrical cells, beneath which are one or two layers of round 

 or polyhedral cells.. All these corpuscles have a relatively 

 large nucleus. The intra-abdominal portion of the duct has a 

 lining similar to that observed in the adult. 



The mucous coat is made up of connective tissue and elas- 

 tic fibres, the former consisting of intersecting fasciculi, the 

 latter of a close network. The membrane is thrown into 

 two or three longitudinal folds or rugae. Near the lower end 

 of the vas deferens, in the ampulla, the longitudinal folds 



