PARASITES OF ANIMALS. 109 
bryos of the common fluke. They are about g}5 to 535 0f an 
inch long, and +53 of an inch broad. The head end is pro- 
vided with a dagger-like boring spine, which can be alternate- 
ly thrust out and withdrawn. It is supposed that these em- 
bryos become parasitic in fresh-water snails, for a time, and 
undergo transformations like those described under the pre- 
ceding species. Their effects and remedies are the same as 
for the common fluke, though owing to their small size they 
would be less injurious, unless in much greater numbers. 
The Stomach-flukes of Cattle (Amphistoma conicum Rud. and 
A. erumentferum Creplin). 
The flukes belonging to the genus Amphistoma, which in- 
cludes, besides the two indicated, A. eaplanatum from the 
bile-ducts of cattle and A. trwncatum from the cat, have a 
small, rather thick, and somewhat conical body, the mouth- 
sucker being at the small end. The large end is rounded and 
bears the other sucker, which is always much larger, near the 
posterior end. The stomach and reproductive organs are 
nearly like those of Distoma. The eggs also produce ciliated 
embryos in the water, and they are supposed to go through 
similar transformations. I do not know that either of them 
have been observed in sufficient numbers to produce serious 
diseases in cattle. 
ACANTHOCEPHALA. 
(Thorn-headed worms.) 
Echinorhynchus gigas Goeze. Figures 74, 75. 
This, which is the only representative of the order hitherto 
found in our domestic mammals, is quite frequent in the intes- 
tine of hogs. It may at once be known by the peculiar pro- 
boscis, which bears several circles of small but sharp hooks, 
which are arranged alternately, in quincunx, mostly toward 
the end of the proboscis (Figure 75). These worms have a 
long roundish body, tapering to the posterior end. The skin 
is generally crossed by numerous transverse wrinkles, but is 
sometimes smoothish. The color is whitish or a little bluish. 
he length of three or four inches, with a 
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