American Representatives of Distoinuin varieg-atuni. 907 



4. HaeiHutoloechus similiplexus n, sp, 



(Fig. 4.) 



This species occiirs in the lungs of Bana virescens Kalm. (Common 

 Frog-, Green Frog) and of Bufo Icntujinosus Shaw (American Toad), 

 In the common frog it is eqnally plentiful with the next species to 

 be described. They occur together, or sometimes one species alone. 

 and sometimes the other, often 3 to 7 in one hing. My mounted 

 specimens vary from 3 to 8 mm in length and I have measnrements 

 of living ones up to 9 mm in length by 2 mm in breadth. Many 

 are spindle-shaped, with the largest diameter at the middle and 

 gradnally rounding and tapering off towards each end, but they are 

 commonly broadest between the middle and the i)Osterior end, with a 

 long tapering anterior end. They are more inclined to appear 

 cylindrical than any of the preceding species but the older worms 

 may be distinctly flattened. 



The cuticie in preserved specimens is about -018 mm thick and 

 is regularly and thickly beset with spines, about "022 mm in length, 

 leaning backwards, with a slight curvature, and extending through 

 the whole thickness of the cuticie, with the points projecting beyond 

 Viewed from the surface, where one can see great numbers of them 

 together, they appear to be in longitudinal and transverse rows, 

 often 'Olö to "02 mm apart but sometimes even less, or more, 

 depending upon the region and the State of contraction of the animal. 

 As is common, they are most abundant at the anterior end. 



The ventral sucker, except when obscured by dark folds of the 

 Uterus, is rather a conspicuous object in this as compared with the 

 other species. It is situated anterior to the middle of the worm 

 and, in a mounted specimen 7 mm long, it measured "38 mm in 

 diameter. The mouth-sucker of the same animal was '41 mm broad 

 by "44 mm long. In a living worm 8'5 mm long the mouth-sucker 

 was '51 X ■ 57 and the ventral sucker • 41 mm across. In a transverse 

 section the ventral sucker was as deep as broad and extended half 

 way through to the dorsal surface, while the breadth of the section 

 was twice its depth. 



The ovary is a small, compact, rounded body, or it may be 

 slightly longer than broad, situated pretty close behind and to one 

 side of the ventral sucker. In a group of twenty, examined with 

 regard to this point, the ovary was on the right side in twelve and 

 on the left side in eight. 



Zool. Jahrb. XVI. Abth. f. Syst, 58 



