279] NORTH AMERICAN MONOSTOMES 61 



or slightly dorsally placed, surrounded by a muscular sucker 220 /x long by 

 375/z wide. Pharynx smaller 140ju long by 125/i wide, adjacent to the 

 sucker, followed by short esophagus which bifurcates to form the large 

 voluminous simple intestinal crura; these end blindly at the end of the 

 middle body third. Genital orifice ventral, near center of body. Testes 

 near the ends of the crura, lobed, the main portion pear-shaped. Ovary 

 in intestinal bifurcation, three branched, each division containing from 5 

 to 10 lobes. Vitellaria well developed, imperfectly symmetrical with 5 to 

 7 groups on the left and 7 to 9 on the right. Uterus much coiled, generally 

 in the posterior half showing a tendency to antero-posterior coiling. Eggs 

 small, 19 to 22 n long by 10 to 12/x wide, containing in the end portion of 

 the uterus a fully formed miracidium. 



The anatomy of these worms has been so thoroughly discussed by Tyz- 

 zer (1918) for the American species, and by Kossack (1911) and Jegen 

 (1917) for the European species that it does not seem necessary to enter 

 into a detailed discussion here. I desire instead to give a comparison of the 

 two forms since Tyzzer found reason based largely on the inconsistency 

 of Kossack's description and figures to declare the American material 

 identical with that found in Europe. 



Ward (1917) after examination of the material reported by Cole (1911) 

 as Monostoma faba pointed out distinct differences between this and the 

 European form described by Kossack (1911). The following is his state- 

 ment, "As a cause of an epidemic among sparrows at Madison Wisconsin, 

 Cole (1911) reported under the name of Monostoma faba a trematode that 

 in reality differs distinctly from the European species. The form of the 

 ovary, the extent of the vitellaria, the dermal spines, and other details of 

 structure disagree with the recent description of Kossack who, moreover, 

 assigned Rudolphi's species." [erroneously attributed to Rudolphi, really 

 Bremser (1831) ] "to his new genus Collyriclum. The American form 

 constitutes a new species in this genus and to it the name Collyriclum colei 

 may be given." 



One year later (1918) the same author restated the differences in the 

 two species as follows: "These specimens differ clearly from the European 

 form in numerous minor details, such as ovary, yolk glands, dermal spines, 

 etc., and demand recognition as a distinct species under the name given 

 here." 



Tyzzer (1918) made a comparison of the two forms based on Kossack's 

 description of Collyriclum faba and concluded that the two species were 

 identical despite certain distinct differences which he explained away on the 

 basis of the discrepancies between Kossack's description and figures. The 

 work of Jegen (1917) which reached America after Tyzzer's had appeared 

 verifies in a large measure the description of Kossack and leaves little 

 doubt that the American material is distinct from Collyriclum faba. The 

 following is the diagnosis of this species as given by Jegen: "In Cysten 



