216 BARKER. 



the anterior end slightly more tapering than the posterior. In the 

 median line at the posterior end is a well defined terminal invagina- 

 tion, which marks the position of the excretory pore. The dorsal 

 surface of the body is strongly arched, the ventral surface slightly 

 cupped. The sides are nearly parallel with the exception of a wide, 

 shallow constriction midway between the ends at the level of the 

 acetabulum. Spines or scales were not found anywhere on the body. 



In the preserved specimens, the anterior third of the body shows a 

 marked and constant tendency to flex ventrad, which gives rise to a 

 well defined and rather deep ventral cup between the oral and ventral 

 suckers. This cup-like depression persists in compressed specimens 

 and possibly functions as a secondary holdfast (PL II, Fig. 8). 



The oral sucker is comparatively large, well defined, nearly circular 

 in outline and ventral in position, with its dorso-ventral axis at right 

 angles to the chief axis of the body. In compressed specimens the 

 oral sucker is 0.80 mm. to 0.82 mm. wide by 0.66 mm. to 0.82 mm. 

 long. In frontal sections it measures 0.82 mm. wide by 0.82 mm. long. 

 The ventral sucker, or acetabulum, lies in the median area at the 

 posterior margin of the anterior half of the body and faces obliquely 

 cephalad. It is of approximately the same size and shape as the oral 

 sucker. It measures 0.60 mm. to 0.74 mm. in length by 0.70 mm. to 

 0.74 mm. in width in compressed specimens and 0.72 mm. by 0.80 mm. 

 in frontal sections. 



The genital pore is not salient and lies in the median line, at the 

 anterior margin of the acetabulum, or else slightly to the left of, and 

 just anterior to the acetabulum. 



In the middle quarters of the body (PI. I, Fig. 2), along the sides, 

 and extending well toward the median line on the dorsal surface, can 

 be seen the characteristic dark colored, convoluted tubular and finely 

 granular vitelline glands in moss-like patches. The uterus appears 

 as a dark coiled mass nearly filling the \entral field of the posterior 

 third of the body. 



Digestive System. — The transversely oval mouth leads into the 

 triangular lumen of the oral sucker, which is 0.90 mm. deep in sagittal 

 sections with thick muscular walls. A thick walled, large and power- 

 ful cup-shape pharynx follows immediately (PL II, Fig. 12). The 

 pharynx measures 0.58 mm. long by 0.52 mm. wide by 0.44 mm. deep 

 in sagittal sections. Eight longitudinal muscular ridges or folds 

 project from the inner' wall of the anterior two thirds of the pharynx 

 into its lumen. Of the four larger or primary ridges, one is dorsal, 

 one ventral, and two lateral; alternating with these are four smaller 



