329] PSEUDOPHYLLIDEA FROM FISHES— COOPER 41 



can scarcely be reconciled with that given here (300+ ), altho his dimensions 

 of the organs agree with these perhaps better than do those by KiessUng or 

 Solowiow. On the other hand there is another factor which may be in the long 

 run more important than a comparison of the details of the anatomy of this 

 evidently highly variable species, namely, the geographical distribution of the 

 hosts. Altho little emphasis can be placed on Fabricius' finding T. gasterostei 

 in the type larval host as long ago as 1780 in Greenland, it must be remembered 

 that here in America there are, as in the case of L. intestinalis, a number of not 

 only the same genera but also of the same species of the larval as well as of the 

 adult hosts as in Europe. From this alone one would be justified in expecting 

 to find the same species of Schistocephalus here, especially since it infests such 

 a number of different host species. But it is a very surprising fact that apart 

 from Linton's report of the larva from Montana evidently no one has up to 

 the present found the form in any of the numerous fish-eating birds of the 

 continent. 



This evident infrequent occurrence of the species is illustrated by the fact 

 that the material used for the present study consisted of only five lots: Nos. 

 61b and 72 from the body cavities of Uranidea formosa, taken from the stomach 

 of Lota maculosa, and 190 from the coelom of Gasterosteus bispinosus atkinsii, 

 of the writer's collection; one lot from Gasterosteus cataphr actus from Alaska; 

 and No. 17.192 of the collection of the University of Illinois from the intestine 

 of Lophodytes cucullatus, the only mature specimen available. 



