354 WILLIAM NICOLL. 



needless to recapitulate the features of resemblance; I shall 

 rather point out the particulars in which they differ. Braun's 

 specimen measured 3'5 mm., so that it is about the same size 

 as an average example of Parorchis acanthus. In the 

 former the oral sucker is much smaller than the ventral 

 sucker, the diameters having a ratio of 1 : 3 ; in the latter the 

 ratio is nearly 1:2. In P. acanthus the pharynx is slightly 

 larger than that of D. jDittacium, and in the latter the 

 testes are much smaller. As a consequence the yolk ducts 

 pass in front of the testes. The yolk glands do not quite 

 reach the ventral sucker anteriorly, but the uterus has several 

 convolutions on either side of the sucker as far forward as 

 the middle of it, and, in addition, it extends very far back, 

 passing even beyond the testes. The convolutions extend to 

 the extreme edge of the body, and thus the whole organ is 

 more extensive than that of Parorchis acanthus. Braun 

 doubts the existence of a true cirrus-pouch, but marks it in 

 his figure. Owing to what is, no doubt, an oversight, he 

 represents an aperture in the centre of the cirrus pouch {c.h.), 

 while on the right side of it the male duct appears to open 

 separately. No mention is made of the excretory system. 



Prom the foregoing considerations there can be little 

 hesitation in including Distomum pittacium, Brn., in the 

 genus Parorchis, which, therefore, comprises P. acanthus 

 as type and P. pittacius (Brn.). 



With regard to the systematic position of the genus I have 

 previously made some remarks. lb displays much affinity 

 with the genus Py gore his, Looss, a member of the sub- 

 family Philophthalminae. It might, though with some diffi- 

 culty, be included under this sub-family, and is, in any case, 

 very near it. It agrees in the size and muscular nature of 

 the body, the relative sizes and development of the suckers, 

 the well-developed alimentai-y system, the position of the 

 genital aperture and genital glands, the situation and small 

 extent of the yolk glands, and the condition of the uterus 

 and ova. ^J^he differences consist in the spines, the cephalic 

 ridge, the long ccsophagus, the weakly-developed cirrus 



