The American Representatives of Distomum cygnoides. 419 



stance, and then ordinarily tapers to a point. The intestinal cseca 

 approach each other from the ovary backwards. but at the vitel- 

 laria tliey are near the side-walls of the body. The vitellaria are 

 sometimes close after the ventral sncker, and never allow more than 

 two or three fokis of the uterns to be seen anterior to them. 

 They are small, rod-like, or crescentic in shape, The ovary, im- 

 mediately behind them, is round, oblong, or reniform, while the two 

 festes are rather larger than the ovary, and are obk)ng', or are 

 considerably larger and then more irreg-ular in outline. The portion 

 of the body behind the ventral sucker is usually so much crowded 

 with eggs that one can not make out the structure, and it is only 

 by very special means or in an occasional case that this can be 

 done. In the drawing I have represented the mode of folding of 

 the Uterus rather than the distribution of eggs. The latter, mea- 

 sured as in the last species, were •ölOX'SßO mm. The worms 

 described were taken from the bladder of Bana virescens, where 

 they may occur in varying numbers — I have notes showing as 

 many as 15 in one frog. They also occur in Rana cateshiana, 

 where, according to my experience, they are smaller and more 

 narrowing from the sucker backwards and have longer and more 

 irregulär festes. 



5. Goi'f/odera amjdiawct Looss. 



This species was called Dist. cygnoides var. A by Bensley, 

 who regarded it as the true species of Zeder. Looss recognized 

 from Bensley's description that it is not the European form but a 

 distinct American species and gave it the above name. It can not 

 be easily confounded with any of the preceding species from which 

 it is especially distinguishable by its small size, its characteristic 

 shape, its large ventral sucker, and its nine festes. A glance at 

 my figures will show that this is the smallest of the five species 

 of Gorgodera occurring here. Mounted preparations ränge about 

 3'75 mm in length and -75 mm in greatest breadth — just behind 

 the ventral sucker. In shape, except for the sucker, it might al- 

 most pass as a miniature of No. 1. The part anterior to the 

 sucker is very narrow, and in the living worm very active, the 

 part posterior broad, flat, and sluggish. In extended individuals 

 the liinder portion increases backwards to the region of greatest 



Zool. Jahrb. Bd. XVII. Abth. f. Syst. 28 



