CLADORCHIS WATSONI (CONYNGHAM) 
133 
The metatrema or distal and modified end of the uterus opens close behind the 
vas deferens : it is a thick, muscular duct which passes backward for a short distance 
in a straight line. Just in front of the anterior border of the testes it enlarges into 
the uterus, and this begins to twist and loop, lying between the dorsally-placed vas 
deferens and the ventrally-placed testes. The uterus contains ova, but not in very 
great quantities ; the eggs are encased in a shell and contain many deeply-staining 
yolk-granules, but little more can be made out. My measurements for an ovum, 
which looked unusually large, were 122 m x 80 /«, but Conyngham gives 130/x x 75 
Undoubtedly the eggs vary in size to a certain extent. The uterus coils a good deal 
over the testes, and at the posterior end of these glands its lumen enlarges, and it 
becomes filled with a glairy-looking coagulum in which the ova lie embedded. 
The ovary or germarium lies close behind the testes, and rather to the right of 
the body : it contains minute ova with large nuclei, closelv packed together in some 
places and loosely in others. The whole, like the testes, is ensheathed in a connecting- 
tissue casing. The oviduct leads from the anterior end and curves back above the 
ovary, it becomes almost immediately surrounded by the shell gland, and may here 
be called the ootype. Close behind the shell gland the ootype receives the opening of 
the vitelline duct, and the inner end of Laurer's canal. The shell gland and the ovary 
come to an end at about the same level as the anterior edge of the posterior sucker. 
There is a well-marked canal of Laurer which passes almost directly dorsalwards and 
opens in the dorsal middle line, just in front of the posterior sucker. 
The yolk glands are conspicuous, follicular structures, which take no stain, but 
remain a somewhat dirty-brown colour, somewhat glistening. They extend forward 
as tar as the reproductive pores, and they lie near the edge of the body, ventral to 
the right and left branches of the alimentary canal. The glands increase in number 
posteriorly, and in the region of the great sucker are very numerous. Their minute 
ductules fuse together and gradually unite into right and left ducts that open into 
the ootype, which is surrounded by the shell gland, and in which the egg is made up. 
Into the same space opens the duct of the yolk reservoir, which is a coiled receptacle, 
full of yolk, lying to the left and opposite the ovarv. 
III. SYSTEMATIC POSITION 
The trematode we have to do with has been described by Mr. H. F. 
Conyngham 1 as a species of the genus Amphistoma, which he calls Amphisloma 
watsoni. Dr. F. Fischoeder has recently pointed out that the name Ampbistomaxs in 
reality a synonym of the genus Strigea, but the original Strigea has since been described 
as Hotostomum macrocephahm, and if Strigea is to be revived it must be for that form. 
Hence Dr. Fischoeder proposes to us the name Parampbistomuni for what we have. 
1. B. M. J., No. 2,281, Sept. 17, 1904, p. 663. 
