NO 
to 
College of Forestry 
From the above it may be readily inferred that the task of working 
out the full hfe history of many Trematodes is beset with many 
difficulties. All of the stages are subject to considerable variation 
and in many the life history is much condensed or abbreviated. First, 
one must know how many hosts are necessary for the complete devel- 
opment of Clinostomum marginatum. The size and form of the 
so-called mature worms in the throat of birds does not differ from 
those released from the cysts in the fish. Some of those which I have 
taken were 10 mm. long and exceed in length those found in birds. 
Thus far very little information has been gained from the study of 
these worms in birds. This is mostly due to the irregular and in 
most cases to the accidental manner in which the birds have been 
studied so far as the problem of fish parasites is concerned. The 
writer hopes that permission may be obtained to make a systematic 
examination of the herons in the Adirondacks this coming summer. 
If they prove to be the real distributors of these parasites, there is 
VE mes 
Original by W. M. Smallwood 
Figure 8. Larval flatworm with a pair of intestinal tubes with a 
few round bodies forming between them. .03 mm. long; .06 mm. 
wide. From snail, Amnicola limosa. Original. 
certainly an additional reason why the law which gives them such 
complete protection should be changed. 
Enough observations are now on record to make it reasonably certain 
that Clinostomum may live for an undetermined length of time in 
several of the water birds. But where the early stages are passed is 
unknown. The wide distribution of this parasite suggests that one 
of several invertebrate hosts may satisfy the requirements of its larval 
development. The snails taken from the stomach of the perch in East 
Pine Pond were identified by Doctor Dall as Amnicola limosa Say. 
This nail is oviparous, depositing a single egg in each capsule. The 
snails, together with other animals, were placed in formalin to be later 
examined. Some of them were partly digested and no special pains 
