684 DR. WILLIAM NICOLL ON 



not very muscular, and is situated TT mm. from the antei-ior end. 

 The neck, therefore, comprises f of the body-length. 



The alimentary canal is highly developed. It consists of a very 

 short prepharynx, with an enormous pharjaix measuring -28 mm. 

 in diameter. The oesophagus is shorter than th§ pharynx, being 

 only about "2 mm. long. It is fairly wide, with well-developed 

 musculature and numerous peri-oesophageal cells. It divides into 

 two very wide diverticula, which extend along the sides of the 

 body to near the posterior end. From the latter they are 

 separated by a loop of the uterus. The ends are slightly inflated 

 and somewhat turned in. 



The excretory system has the same genei-al structure as in the 

 two previous species. The main stem of the excx'etory vesicle 

 divides close behind the shell-gland into two limbs, which extend 

 a short distance in front of the ventral sucker. From the vesicle 

 numei'ous twigs are given off, which divide and subdivide in the 

 lateral fields to form an intricate anastomosis. The most peculiar 

 feature of the excretory system, however, is the pigmented con- 

 dition of the excretory tubules, which renders them strikingly 

 conspicuous and marks out their course with great distinctness. 

 This feature renders thespecies unique amongst the Lepodermatidse. 

 The pigmentation is due to the excretory granules, which are 

 almost black in colour, and which fill the tubules. Only a few of 

 these are to be met with in the vesicle. A main excretoiy tubule 

 runs along the greater part of the length on each side of the body, 

 venti^al to the intestinal diverticula. In front of the ventral 

 sucker it divides into small branches, one of which runs in to join 

 the vesicle, and another runs forward to the oral sucker. At the 

 posterior end it also divides into several branches. It is impossible 

 to say whether this pigmented condition occurs in life or is 

 a post-mortem appearance, but it was certainly present in all the 

 specimens. 



The genital aperture is median, just over the intestinal bi- 

 furcation ("3 mm. in front of the ventral sucker). It shows 

 a tendency to be deflected very slightly to the left side. In every 

 specimen the long, thick cirrus was exserted. The cirrus-pouch 

 is short and stout, in some cases being almost globular. Its 

 posterior end lies dorsal to the middle of the ventral sucker, but 

 it may extend beyond this to almost the posterior border of the 

 sucker. The pouch has an external wall composed of very thick 

 longitudinal muscle-fibres, with an inner layer of much smaller 

 circular fibres. It contains a small, slightly-coiled vesicula semi- 

 nalis, a small bulbous pars prostatica, with numerous prostatic 

 cells, and a long ductus and unarmed cirrus. As already men- 

 tioned, the latter was exserted in every case, so that the 

 arrangement depicted in fig. 8 (PI. XXVIII.) must be regarded as 

 hypothetical. The vesicula, prostate, and cirrus all have a very 

 well-marked layer of longitudinal muscle-fibres. 



The testes are situated obliquely, the left being well in front of 

 the right, but not entirely so. The former lies about -3 mm., and 

 the latter "8 mm. behind the ventral sucker. They are large ovoid 



