180 



TRANSPORTATION OF THE GAMETES 



tion of sperm to the contents of the tubules. As the seminiferous tubule is 

 blind at its distal end, increased pressure of this kind would serve efficiently 

 to push the contained substance forward toward the efferent ductules con- 

 necting the testis with the reproductive duct. 



2) Activities Within the Efferent Ductules of the Testis. The time required 

 for sperm to traverse the epididymal duct in the guinea pig is about 14 to 

 16 days. However, when the efferent ductules between the testis and the 

 epididymal duct are ligated, the passage time is increased to 25 to 28 days 

 (Toothill and Young, '31). The results produced by ligation of the ductuli 

 efferentes in this experiment suggest: (a) That the force produced by the 

 accumulation of secretion within the seminiferous tubules and adjacent ducts 

 tends to push the sperm solution out of the seminiferous tubules into the 

 ductuli efferentes and thence along the epididymal duct, and/or (b) at least 

 a part of the propulsive force which moves the contents of the seminiferous 

 tubules through the rete tubules and efferent ductules and along the epididymal 

 duct arises from beating of cilia within the lumen of the efferent ducts. The 

 tall cells lining the latter ducts possess cilia which beat toward the epididymal 

 duct. As the sperm and surrounding fluid reach the efferent ductules, the 

 beating of these cilia would propel the seminal substances toward the epi- 

 didymal duct. 



b. Movement of the Semen Along the Epididymal Duct 



1) Probable Immotility of the Sperm. The journey through the epididymal 

 duct as previously indicated is tedious, and secretion from the epididymal 

 cells is added to the seminal contents (fig. 99). Sperm motility evidently is 



Fig. 99. Human epididymal cells. (Slightly modified from Maximow and Bloom: A 

 Textbook of Histology, Philadelphia, W. B. Saunders Co.) These cells discharge secretion 

 into the lumen of the epididymal duct. Observe large, non-motile stereocilia at distal 

 end of the cells. 



