NEW PARASITE FROM THE CRAYFISH. 67 



for they indicate that the young worm develops actively during 

 .encystment, and that here self-fertilization must take place. A 

 fuller study of this point is desirable. 



In the fish the parasite has been found only in the stomach. 

 Both cysts separated from the crayfish, and the free worms are 

 found. B. nodulosa is reported from the intestine of fishes and 

 B. auriculata is also an intestinal parasite. 



The body form is nearly cylindrical, in contrast with the elon- 

 gate neck and almost leaf-shaped body of B. nodulosa. This 

 contrast is well seen by comparing Figs. I or 7 with Fig. 10 of 

 Looss. The latter is a young stage in which the vitellaria are 

 not as yet developed, while both of the Chautauqua specimens pos- 

 sess them and the uterus contains eggs. My specimens differ 

 considerably in length, owing to the fact that they go on growing 



o j mm 



FIG. 4. Transverse section passing through the oral sucker in the level of the lat- 

 eral processes. Cam. luc. X 5- l.o.f., lateral oral papilla ; b.w., body wall,/<2r., 

 parenchyma; o.s. , oral sucke'r. 



longer after maturity. The longest one that I have seen meas- 

 ured 3.0 mm. in length by 0.9 mm. in width (in the preserved 

 and mounted state). I have seen specimens fully developed 

 sexually measuring only 0.9 mm. in length by 0.2 mm. in width. 

 The oral sucker is very large, so that it fills completely the an- 

 terior end of the body. It is furnished with remarkable muscular 

 processes, six in number which give the worm a very character- 

 istic appearance. Four of these processes or papillae are blunt, 

 and extend forward from the dorsal and anterior end of the 

 body. In a ventral view of the animal they are seen extend- 

 ing slightly beyond a thin layer of the body wall which forms the 

 anterior boundary of the body. The other two papilla; are at the 

 posterior level of the oral sucker, and ventral, on the opposite 



