182 



TRANSPORTATION OF THE GAMETES 



EXTERNAL 

 LONGITUDINAL 

 MUSCLE 



OUTER CIRCULAR 

 MUSCLE 



N T E R N A L 

 LONGITUDINAL 

 MUSCLE 



TUNICA PROPRIA 

 EPITHELIU M 



LUMEN 



EPITHELIUM 



TUNICA PROPRIA 

 INTERNAL 



LONGITUDINAL 

 MUSCLE 



OUTER CIRCULAR 

 MUSCLE 



EXTERNAL 

 LONGITUDINA L 

 MUSCLE 



Fig. 100. Highly muscular character of the ductus deferens. This particular drawing 

 was made from a longitudinal section of the ductus deferens of a young rat. Observe cilia 

 (stereocilia?) on inner surface of epithelium, lining the lumen. 



3) Summary of Factors Which Propel the Seminal Fluid from the Testis 

 to the External Orifice of the Reproductive Duct in the Mammal. The fol- 

 lowing probable influences are at work, propelling sperm from the testis 

 through the accessory ducts in the mammal: 



( 1 ) The pressure of accumulated secretions within the seminiferous tubules 

 may push the sperm outward toward the accessory ducts; 



(2) the beating of cilia and accumulation of secretion within the ductuli 

 efferentes is another probable force which ushers the sperm and semi- 

 nal fluid forward; 



(3) the secretion from the cells of the anterior epididymis and the body 

 of the epididymis may serve, together with weak muscle contraction, 

 to advance the sperm mass toward the posterior epididymis; 



