i 3 o THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
I am greatly indebted to Dr. Stephens for supplying me with the material upon 
which this paper is based. 
I have discussed the systematic position of this parasite at the end of this article. 
Here I will only mention that it belongs to the family PAR J M PHIS TOMIDAE 
(Fischoeder) and to the sub-family CLADORCHINAE. Allied to it and belonging 
to the same sub-family is the genus Gastrodiscus, which is represented amongst the 
human parasites by Gastrodiscus bominis (Lew and McConn). 1 This latter seems to 
have been observed but twice in the human body — once in a native of Assam and 
once in an Indian. It occurred in great numbers in the colon and coecum. Its 
normal host is probably the genus Equus, both in Africa and in India. 
It seems reasonable to surmise that in the case of Cladorchis watsoni also man is 
but an occasional host, and that the normal host is some herbivorous animal. We 
know nothing of the life history of either form, but from our knowledge of 
trematodes in general it seems improbable that the habit of eating raw meat has any- 
thing to do with the presence of the parasite in the human intestine. Gastrodiscus 
kominis and Cladorchis watsoni are the only members of the family PARAMPHIS- 
TOMIDAE hitherto found in man. With the exception of Schistosomum haematobium 
(Bilharz) ( = Bilharzia), which is now placed in Looss' family, the SCH1STOSO- 
MIDAE, all the other man-infesting trematodes — and there are about a dozen of 
them— belong to the family FASCIOLIDAE (Raill). 
II. ANATOMY 
Alimentary Canal. — There is no true sucker at the anterior end. The mouth is 
a simple aperture leading into a pharynx, the walls of which form an almost spherical 
bulb. The lumen is lined with chitin, and the bulb is separated from the general 
parenchyma of the body by a basement membrane. Between the basement membrane 
and the chitinous lining lies a loose tissue crossed by numerous muscle fibres, which 
mostly run in a radial direction, but a few run circularly. 
At first the lumen of the pharynx is compressed from side to side, but after 
about 30-35 sections from the anterior end the lumen has become depressed from 
above downwards, and just here are found two short dorsal and ventral valves pro- 
jecting like tongues into the lumen only directed backwards. They are attached 
anteriorly and free posteriorly. Behind these valves the lumen becomes diamond- 
shaped, the long axis being the transverse one, and here the bulb is at its largest and 
occupies a good deal of the area within the body wall. Its wall is also now divided 
into an outer and inner layer by a well-marked layer of circular muscles. The inner 
layer consists largely of radiating muscle fibres. The whole bulb lies somewhat freely 
in the very loosely vacuolated parenchyma, which seems to form a space around it 
transversed only by a few sparse threads of protoplasm. 
1. P. Asiat. Hoc, Bengal, 1876, p. 182. 
