224 BARKER. 



course are folded or pleated, which gives rise to distinct but irregular 

 pockets along their course. 



Male genitals. — One of the most characteristic features of this tre- 

 matode is the testes (Fig. 22), twelve in number, arranged in two 

 groups of six each. They are small, irregular, lobed bodies situated in 

 the posterior third of the worm lying on each side of the body immedi- 

 ately ventral to the terminal portions of the intestinal caeca. Taken, 

 together the testes have the shape of a horseshoe, with its open end 

 directed cephalad and extending from the level of the ovary and 

 vitelline glands caudad to the ends of the intestinal caeca. The testes 

 may be separated from, or may overlap, one another. A small duct 

 connects all the testes comprising each group and a larger duct, the 

 vas efferens, passes mediad from the anterior testis of each group. The 

 vas efferens from the left side passes transversely across the body and 

 unites with the short vas efferens from the right side. The vasa effer- 

 entia vmiting from a short vas deferens, which passes cephalad in the 

 right mediolateral field and joins a long tubular convoluted seminal 

 vesicle, which runs anteriorly, mediad to the right intestinal caecum, 

 and enters the cirrus pouch (Fig. 22). The seminal vesicle is lined 

 with a high columnar epithelium. 



The cirrus pouch (Figs. 22, 20) is a very muscular elongated sac 

 lying between the intestinal caeca at the level of the posterior margin 

 of the anterior fourth of the body. It extends obliquely across the 

 body from right-dorsal to left-ventral and enters the male genital pore. 

 It is provided with an outer thick sheet of strong longitudinal muscle 

 fibers and an inner (toward its lumen) thin sheet of circular muscle 

 fibers. Parenchymal tissue fills the space between these muscle sheets. 

 The seminal vesicle enters the base of the cirrus pouch, where it 

 enlarges to form a short tubular pars prostatica, which is surrounded 

 by the prostate cells. The pars prostatica enters a cone-shaped 

 cavity, the ductus ejaculatorius, which is one-fourth of the length of 

 the pouch and is lined with high columnar epithelial cells having the 

 appearance of coarse cilia. The ductus ejaculatoris is followed by a 

 narrow canal which forms the lumen of the cirrus (Fig. 20). 



The cirrus is strongly developed and consists of two distinct regions, 

 both of which are protrusile. The basal proximal portion is bulbous 

 and in one specimen measured 0.33 mm. long by 0.25 mm. in diameter; 

 the distal portion is more slender and tapering and in the same speci- 

 men measured 0.50 mm. long bv 0.125 mm. in diameter. The distal 

 portion can be retracted into the bulbous portion. The entire 

 extruded cirrus may be 0.85 mm. long. The cirrus is covered with a 



