236 



NORMAL HISTOLOGY. 



cuboidal type. Numerous particles of pigment are common in their cyto- 

 plasm. The tunica propria contains a dense network of elastic fibres within 

 its outer zone. The unusually robust musculature of the vas, from .8-1.2 

 mm. thick, constitutes approximately four-fifths of the entire wall and includes 



unstriped fibres arranged as 

 an outer longitudinal, a mid- 

 dle circular, and an inner 

 longitudinal layer, the last 

 mentioned layer being much 

 less developed than the outer 

 and middle strata. Theji&rous 

 coat is composed of closely 

 arranged bundles of fibrous 

 tissue and many elastic fibres. 

 In the funicular part of the 

 duct, between the epididymis 

 and the abdominal wall, the 

 fibrous coat contains strands 

 of unstriped muscle, which 

 belong to the coverings of the 

 cord and constitute the so- 

 called internal cremaster. 



The ampulla, the some- 

 what flattened fusiform en- 

 largement of the vas just 

 before it becomes the ejaculatory duct, is uneven and humpy in contour 

 owing, to the sacculations and tortuosity of the canal and the short diver- 



FIG. 286. Cross-section of vas deferens. X 15. 



FIG. 287. Transverse section of ampulla of spermatic duct (vas deferens). X 18. 



ticula that pass from the main duct at various angles. In its general struc- 

 ture the ampulla corresponds with the vas deferens, its walls, however, 

 possessing a much thinner and less regular muscular coat the inner longi- 

 tudinal layer disappearing, the outer one being imperfect, and the orderly 



