THE MALE GENITAL TRACT. 



819 



(3) The vas defer ens has a broad wall, which is composed 

 mainly of three layers of smooth muscle-fibers an inner and 

 outer longitudinal and a middle circular layer. (See Fig. 372.) 



The most internal mucous layer, when the tubule is empty, is 

 arranged in folds, and covered with a single layer of columnar 

 epithelia. The only vas deferens which I have examined exhib- 

 ited ciliated columnar epithelium ; all authors claim, however, 

 that cilia are not present. The bundles of the longitudinal mus- 

 cle-layers are loosely arranged, and freely intermixed with 

 fibrous connective tissue abundantly furnished with elastic fibers, 



FIG. 372. VAS DEFERENS. TRANSVERSE SECTION. 



E, folds of the mucosa, covered witli columnar epithelia ; M, mucous layer, composed of 

 delicate bundles of connective tissue ; C 1 , inner longitudinal, d, outer longitudinal, layer of 

 bundles of smooth muscle-fibers, freely intermixed with connective tissue ; T, circular mus- 

 cle-layer ; O, adventitial connective tissue, carrying the larger blood-vessels. Magnified 100 

 diameters. 



while in the circular layer the muscle-bundles are arranged more 

 closely. The most external layer is composed of loose, fibrous 

 connective tissue, rich in blood-vessels, lymphatics, and nerves. 



(4) The ampulla of the vas deferens and the seminal vesicles 

 have walls considerably thinner than those of the vas deferens 

 proper. In the ampulla the mucosa has abrupt folds, and the 



