AET. IJl NEW SPECIES OF TEEMATODE WORMS — CHANDLER 5 



equivalent size the oral sucker measures 120m to 128m transversely 

 and 86m to 115m in length. The acetabulum is also markedly larger 

 and situated farther posteriorly. The loose arrangement of the 

 uterine coils as compared with the solid massing of eggs in H. tricolor 

 is very marked. The sizes of the testes and ovary are also different. 

 In the two specimens of H. tricolor mentioned above, which were lent 

 for comparison, the posterior testis measures 236m by 157m in one 

 and 248m by 133m in the other. In my specimens of H. texensis the 

 posterior testis is much more nearly round, with a diameter of from 

 110m to 115m, but in Doctor Francis's specimens the posterior testes 

 are more oval and measure from 170m to 228m in the larger, trans- 

 verse, diameter. This slide was prepared over 30 years ago and the 

 testes may have become considerably compressed, as may also be the 

 case with Stiles and Hassall's specimens. Other differences exhibited 

 by H. texensis are the very much larger size of the extruded penis 

 (80m by 32m in H. tricolor and 140m to 200m by 40m to 60m in H. tex- 

 ensis); the absence of an esophagus between the pharyngeal bulb 

 and the bifurcation of the ceca; the less profuse and more scattered 

 vitellaria; the unusual development of the prostate glands; and the 

 very distinct Laurer's canal. 



REFERENCES CITED 



Hall, M. C, 1916. Hasstilesia tricolor (Stiles and Hassall, 1894), a common 

 parasite of rabbits in the United States. Journ. Amer. Vet. Med. Assn., vol. 

 47, new ser., vol. 1, pp. 453-456. 



Stiles, C. W. and Hassall, A., 1894. Notes on Parasites 29-30. Bull. Soc. 

 Zool. de France, Paris, vol. 19, pp. 160-162, abstract of: A new species of 

 intestinal fluke, Distoma tricolor, in the cotton-tail rabbit (Lepus sylvaticiis 

 Bachman) and in the northern hare (L. americanus Erxleben). Vet. Mag., 

 Philadelphia, vol. 1, pp. 729-737. 



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