678 DR. WILLIAM NICOLL ON 



The cuticle is fairly thick, somewhat deciduous, and is studded 

 throughout its whole extent by stout salient spines. These are 

 regularly arranged, and become sparse towai-ds the posterior end. 

 The underlying musculatui'e has the usual formation. 



In an average adult specimen of 6*5 mm. length the oral 

 sucker has a diameter of -45 mm. It is subterminal, globular, 

 and its aperture has a marked muscular rim. The thickness of 

 its wall is about "13 mm. In the same specimen the ventral 

 sucker measures '66 mm. It is also globular, slightly flattened, 

 and its wall is "18 mm. thick. The sucker ratio is, therefore, 

 very approximately 2:3. The diameter of the sucker relative to 

 the body-length diminishes as the animal increases in size. 

 Thus, in the smaller specimens the ventral sucker is -^ of the 

 body-length, while in the largest it is only -^j. The ventral 

 sucker is situated about ^ of the body-length from the anterior 

 end. In this respect, again, the young specimens difler from the 

 older ones in that they have the ventral sucker relatively further 

 back. 



There is a very short prepharynx ; usually the pharynx is 

 contiguous with the oral sucker, and it measures •23x'17 mm. 

 The oesophagus is about | of the length of the phai-ynx, although 

 it is longer in young specimens. The intestinal bifurcation takes 

 place well in front of the ventral sucker. The intestinal diverticula 

 run almost parallel to the edges of the body. They bend in a 

 little just behind the ventral sucker, but they are pressed out 

 again by the testes. At their termination, just behind the 

 posterior testis, they usually turn in a little. Their ends are 

 abovit I of the body-length from the posterior end. They are 

 comparatively narrow tubes, and their wall is crinkled on the 

 inner side. The outer side is plain. They are lined by a layer 

 of low epithelium. The cesophagus has the usual cuticular lining. 

 Throughout their whole extent the diverticula are somewhat 

 ventral in position. 



The excretory system is characteristic and agrees with Odhner's 

 supposition as to its form in the group to which this species belongs. 

 The vesicle consists of a fairly broad main stem, opening at the 

 tip of the tail and passing forwards to the shell-gland, where it 

 divides into two limbs. These diverge to form a Y, and each passes 

 over the edge of the ventral sucker and terminates halfway 

 between the sucker and the intestinal bifurcation. The main stem 

 is pressed close to the dorsal surface, but the limbs are not quite 

 so dorsal in position. They eventually come to lie close up to the 

 intestinal diverticula and separate these from the uterus and 

 cirrus-pouch respectively (PL XXVII. fig. 4). The main stem is 

 much compressed dorso-ventrally, but the limbs are round or com- 

 pressed ti'ansveisely. In addition to this central system, however, 

 numerous lateral twigs are given oft" from the stem and limbs. 

 These all radiate outwards towards the edges of the body, dividing 

 and subdividing and eventually forming an intricate anastomosis 

 (PL XXVII. fig. 3). The entire lateral fields of the body are thus 

 filled with a complex network of excretory tubes, and the amount 



