DISTRIBUTION OF CLINOSTOMUM MARGINATUM. 363 



5. ON THE OCCURRENCE OF THE WORM IN THE HERON. 

 A single specimen of the heron sent me by express from Nebish 

 in October happened to be infected with this parasite and fur- 

 nishes all that I have myself observed on this point. The bird 

 had been shot and had been dead a day or two before it came into 

 my possession. The worms were still alive and suitable for 

 fixation and preservation for histological study. The worms 

 were found in considerable numbers adhering to the wall of the 

 throat by means of the anterior end used as a sucker in the 

 manner referred to above. On being removed they were found 

 to be mobile but no data as to their movements were recorded. 

 The stomach and intestine of the heron were carefully examined 

 to ascertain whether those organs were infected or not. No 

 worms were found there. The stomach however contained the 

 remains of the bodies of five fishes in various stages of digestion 

 all of which were too decomposed for recognition with entire 

 certainty but their elongate shape, their size and the fauna of 

 the region made it virtually certain that they were sepcimens of 

 the yellow perch. This observation furnishes the evidence of a 

 connection between the fish and the final host. The liberation 

 of the worms in the stomach and their migration of the worms 

 in the stomach and their migration and adhesion to the wall of 

 the throat is of course the first event of their life in the avian 

 host followed by the production of eggs and their passage to 

 the uterus where we find them in great numbers in the specimens 

 taken from the heron. It is not exactly clear why the eggs are 

 not passed directly from the body of the heron after the manner 

 general in the flukes. Here however there is a large uterus into 

 which the eggs pass and where they accumulate, for reasons as 

 yet unknown. The eggs when they are expelled from the fluke 

 must pass down the alimentary canal of the heron and fall with 

 the feces in the water or less probably on the ground, where they 

 make their way to the first host. The eggs in the uterus show 

 no signs of development so that the ontogeny remains for the 

 present a wholly unknown quantity. 



SUMMARY. 



i. The first host and early life-history of C. marginatum are 

 entirely unknown. 



