290 



EXTERNAL GENERATIVE ORGANS, BY E. KLEIN. 



right angles to each other an internal circular, and an external 

 longitudinal. Both consist of unstriated muscular fibres alone. 

 At the commencement of the vas deferens, and extending to a 

 distance of two centimeters (three-fourths of an inch) from the 

 epididymis, there is always an internal longitudinal layer, but 

 elsewhere this is only represented by a few fasciculi lying 

 internally to the circular layer. 



Fig. 211. 



Fig. 211. Transverse section made through the commencement of 

 the vas deferens of an adult, a, Epithelium ; 6, mucosa ; c, in- 

 ternal ; d, middle ; e, external muscular layer ; /, fasciculi of the 

 cremaster internus ; gr, a vein with muscular walls. Magnified with 

 Hartnack's objective system No. 2, ocular 3. 



In adults the thickness of this internal longitudinal layer 

 varies from 0'06 to O'l of a millimeter. The thickness of the 

 middle circular layer diminishes from the commencement of 

 the vas deferens towards the ampul-la, but at this part it re- 

 acquires its original thickness, amounting to about 0'5 of a 

 millimeter. The muscular layers in the newly born child are 



