^T.4 FOUR NEW TREMATODE WOEMS PRICE 6 



The above description is based entirely upon specimens collected 

 from a muskrat and forwarded to the Zoological Division of the 

 Bureau of Animal Industry for identification by Dr. Ronald G. 

 Law, Experimental Fur Farm, Kirkfield, Ontario, on August 3, 

 1928. Specimens of what appear to be this form (U.S.N.M. No. 

 29221) were collected from a California gull {Larus calif amicus) 

 by Dr. E. B. Cram, August 8, 1929, at Klamath Falls, Oreg. The 

 specimens from the gull were located in the glands of the pro- 

 ventriculus, but aside from a slightly more cylindrical shape they 

 appear to be specifically identical with the form from the muskrat. 

 The slight difference in shape may be accounted for in part by the 

 location of the worms in their respective hosts and in part by the 

 methods employed in the fixation of the two lots of specimens. All 

 essential measurements of the specimens from the gull intergrade 

 with those of specimens from the muskrat to such an extent that it 

 is unlikely that they represent separate species. The only species of 

 the genus which resembles Psilostomum ondatrae sufficiently to war- 

 rant comparison is P. varium^ a species described by Linton (1928) 

 from the loon, Gavia immer. P. ondatrae may be differentiated 

 from P. Valium on the size and position of the testes, extent of the 

 vitellaria, and on the position of the genital pore. In P. varium 

 the testes are smaller and situated more anteriad than in P. ondatrae; 

 the vitellaria are distinctly separated in the preacetabular portion 

 of the body in the former sj)ecies, while in the latter these glands 

 meet in the median line immediately caudad of the pharynx; the 

 genital pore is located at the intestinal bifurcation in P. varium and 

 about midway between the anterior margin of the acetabulum and 

 the intestinal bifurcation in P. ondatrae. 



Family ECHINOSTOMIDAE Loess, 1902 

 Subfamily Echinochasminae Odhner, 1910 



ECHINOCHASMUS SCHWARTZI, new species 

 Figure 2 



Specific diagnosis. — Echinochasmus: Body spindle-shaped in out- 

 line, 1.5 to 2.1 mm. long by 449/^ to 620/* wide in the region of the 

 anterior testis. Cuticular spines are present in the anterior part of 

 the body. These spines are scalelike and arranged in alternating, 

 transverse rows; the rows anterior to the acetabulum are close to- 

 gether, while posterior to the acetabulum the rows are progressively 

 farther apart and the number of spines decreases; spines finally 

 disappear near the level of the posterior margin of the posterior testis. 

 In specimens from the muskrat most of the cuticular spines were mis- 

 sing: owine: to the fact that the worms had been dead for several hours 



