1246 



SPLANCHNOLOGY 



walls are dense, and its canal is extremely small. At the fundus of the bladder 

 it becomes enlarged and tortuous, and this portion is termed the ampulla. A small 

 triangular area of the fundus of the bladder, between the ductus deferentes laterally 

 and the bottom of the rectovesical excavation of peritoneum above, is in contact 

 with the rectum. 



Ductuli Aberrantes. A long narrow tube, the ductulus aberrans inferior (vas aberrans of 

 Holler}, is occasionally found connected with the lower part of the canal of the epididymis, or 

 with the commencement of the ductus deferens. Its length varies from 3.5 to 35 cm., and it 

 may become dilated toward its extremity; more commonly it retains the same diameter through- 

 out. Its structure is similar to that of the ductus deferens. Occasionally it is found unconnected 

 with the epididymis. A second tube, the ductulus aberrans superior, occurs in the head of the 

 epididymis; it is connected with the rete testis. 



Paradidymis (organ of Giraldes). This term is applied to a small collection of convoluted 

 tubules, situated in front of the lower part of the cord above the head of the epididymis. These 

 tubes are lined with columnar ciliated epithelium, and probably represent the remains of a part 

 of the Wolffian body. 



Structure. The ductus deferens consists of three coats: (1) an external or areolar coat; (2) a 

 muscular coat which in the greater part of the tube consists of two layers of unstriped muscular 

 fiber: an outer, longitudinal in direction, and an inner, circular; but in addition to these, at the 

 commencement of the ductus, there is a third layer, consisting of longitudinal fibers, placed 

 internal to the circular stratum, between it and the mucous membrane; (3) an internal or mucous 

 coat, which is pale, and arranged in longitudinal folds. The mucous coat is lined by columnar 

 epithelium which is non-ciliated throughout the greater part of the tube; a variable portion of 

 the testicular end of the tube is lined by two strata of columnar cells and the cells of the 

 superficial layer are ciliated. 



Pro s b a,t 



FIG. 1152. Fundus of the bladder with the vesiculae seminalea. 



The Vesiculae Seminales (Seminal Vesicales) (Fig. 1152). 



The vesiculae seminales are two lobulated membranous pouches, placed between 

 the fundus of the bladder and the rectum, serving as reservoirs for the semen, 

 and secreting a fluid to be added to the secretion of the testes. Each sac is somewhat 

 pyramidal in form, the broad end being directed backward, upward and lateralward. 

 It is usually about 7.5 cm. long, but varies in size, not only in different individuals, 

 but also in the same individual on the two sides. The anterior surface is in contact 

 with the fundus of the bladder, extending from near the termination of the ureter 



