1182 



BULLETIN OF THE BUREAU OF FISHERIES. 



mm. long in that from another host. In the latter it was noticeable that the 

 suckers protruded very conspicuously and the body was much smaller in caliber 

 than in the specimens from the salmon and the smelt. Yet in the absence of 

 any structural differences I am forced to conclude that this contrast in size and 

 general external appearance is due to some slight difference in the technique 

 employed or in the condition of the parasites when they were preser\'ed. This 

 is all the more probable when one considers that in one case the specimens from 

 Esox were identical in appearance with those from the salmon. This parasite 

 was found in all but one of the dozen specimens of Esox reticulatus examined, 

 being present in the stomach in numbers of i to 80 in each host. In two cases 

 a single specimen was found in the intestine, perhaps due to some post-mortem 

 wandering on the part of the parasites. In 4 specmens of Anguilla chrysypa 

 out of 9 examined I also found Azygia sebago in the stomach, but in small num- 

 bers only, averaging 3 to each host. Finally 2 of these distomes were found 

 in a single Perca flavescens, here also in the stomach. 



In order to give a ready comparison, I append hereto a table of similar 

 measurements from a series of this distome taken from the various hosts men- 

 tioned. The difference in length indicates in part age and in part method of 

 preservation. In fact, it is difficult to achieve any uniformity among speci- 

 mens so exceedingly active as this species. 



Measurements of Azygia sebago. 



a Much elongated: poor technique; preserved by helper. 



The question naturally presents itself, Has this form been seen by others 

 previous to the present date? The records on the subject are scanty, but they 

 throw some light on the question. 



