1 64 KESKAKCHES IN HELMINTHOI.OG V AND PARASITOLOGY. 



pointed setapeds in four longitudinal rows are in fascicles of three 

 or four to each in advance of the girdle and two or three to each 

 behind it. 



In the Enchyiyccu$ of our forests I have repeatedly observed an 

 infusorial parasite occupying the body cavity, sometimes in consid 

 erable numbers, mingled with the normal discoid corpuscles. I 

 propose to name it Anoploplirya niodcsta. In the Enchytricits of the 

 meadows of Atlantic City I ob.ser\'ed a different infusorian occupying 

 the same cavity, remarkable for its great proportionate length. This 

 I propose to name Anoplophrya fioiicnlus. 



Wishing to ascertain whether the latter did not likewi.se infest the 

 Enchytrceus of our neighboring forests I recently collected a number 

 of little worms at Media, Delaware county, Pa. These I oV)tained 

 from beneath a stone lying in my path to Swarthmore College. They 

 appeared to be robust specimens oi Enc/iytrcsus vermicularis , for which 

 I took them to be. Investigation at home proved them to be differ- 

 ent and generically distinct from previous known forms. The worms 

 possess but two rows of setapeds, in.stead of four, as in most others 

 of the family. Hoffmeister and Gruby described the genus Plircorychs 

 as having only two rows of setapeds, but Leydig has shown this to 

 be an error. In view of the error, I carefully repeated my exam- 

 ination of the little worms from Media, and am convinced that the\' 

 possess two rows of setapeds, while in Enchytrceus I always found 

 four. So much do the former otherwise resemble the latter that it 

 would appear as if they formed a genus directly evolved from Enchy- 

 trceus merely by the suppression of a pair of the four rows of setapeds. 



The new genus pre.sents the following characters, and may be 

 indicated by the accompanying name : 



Distichopus. — Form and color as in Enchytrceus, with a well-pro- 

 duced girdle. Setapeds in a single row on each side ventrally, in 

 divergent fa.scicles of four in advance of the girdle and of three 

 behind it. 



Distichopus Silvestris. — Body cylindrical, white, translucent, with 

 a well-produced girdle of whiter color. Upper lip short, conical 

 blunt ; anal segment thicker than the penultimate, brownish and 

 punctate ; anus quinquiradiate. Ten setigerous segments in advance 

 of the girdle, with fascicles of usually three or four setapeds ; fifty- 

 five setigerous segments behind the girdle, with usually two or three 

 .setapeds. Oral and anal segments without setapeds. Setapeds 

 shorter and stouter than in Enchytjreus vcrmicularis, curved at the 

 root, swollen at the middle, and straight towards the point. Length 

 from nine to fifteen lines. 



