236 S. J. JOHNSTON. 



ture towards the ventral side, so that the shape of the body 

 viewed from the side is like an open (fig. 18 and 19). The 

 average breadth of the male viewed from the side and 

 measured from the lateral border, forming the boundary of 

 the gynecophoral canal, to the middle of the dorsal surface 

 is 0*4 mm. The gynecophoral canal is deep, and is wrapped 

 round the female (fig. 22). The limbs of the intestine, both 

 the paired and unpaired tracts, are beset with numerous 

 short diverticula throughout their whole length. The four 

 commissures form two small loops which are connected by 

 an unpaired piece. Behind the second loop the intestine 

 proceeds to the posterior end as a single unpaired tube. 



The Excretory system- consists of a very short Y-shaped 

 vesicle opening at the extreme posterior end, with two fine 

 ciliated tubes given off from the anterior limbs of the Y. 

 In the female also it has a similar form. The genital 

 opening is placed about 0*125 mm. behind the ventral 

 sucker, about midway between the middle line and the 

 lateral border. The cirrus sac is moderately developed 

 and completely encloses the vesicula seminalis, which is 

 elongated pear-shaped. Comparatively large prostate cells 

 lie in the parenchyma of the cirrus sac. The testes begin 

 0*2 mm. behind the genital opening and extend backwards 

 throughout the second quarter of the body length, consist- 

 ing of eighteen to twenty rounded follicles, which lie 

 symmetrically placed, one behind the other, midway 

 between the intestinal limbs. 



In the female the anterior part of the body has a very 

 even diameter (0*058 mm.) throughout its length, while the 

 posterior flattened part is 0*136 mm. wide. The length of 

 the anterior part is 2*65 mm., that of the posterior 1*85 mm. 



The mouth opening is ventral, a little (0*03 mm.) behind 

 the anterior end, and there is no oral sucker. The ventral 

 sucker is, however, well developed (fig. 22), and stalked as 



