1890.] NATURAL SCIENCES OF PHILADELPHIA. 415 



of the body and filled with yellowish ova; testicles paired, spherical, 

 situated behind the ventral acetabulum ; genital apertures behind the 

 oral acetabulum. Length from 2 to 3 mm. by 0'5 to 0'75 nun. ; in 

 movement elongated to twice the length and most narrowed in 

 advance of the ventral disk ; the latter to 0*5 mm. Ova 0'02 by 

 0-016 mm. 



Several hundred attached to the lining of the stomach from its 

 commencement to the end of its ccecal extremity. From the Skip- 

 jack, Trlchiurus lepturns. 



23. Distomum ischnum n. s. 



Body long, narrow band-like with the ventral disk at the anterior 

 fourth ; smooth, translucent, brownish with lateral black lines due 

 to the long tortuous and sacculated forks of the intestine ; anterior 

 extremity slightly narrower, with rounded head and unarmed ; pos- 

 terior extremity transversely corrugated, with parallel sides and 

 rounded truncate, emarginate end ; ventral disk about half the width 

 of the body ; oral disk smaller ; uterus coiled along the middle of 

 the body and distended with ova. Length 8 mm. by 0"875 mm. 

 wide ; ventral disk 0*625 mm. Ova 0*02 by 0'012 mm. 



A dozen specimens from the mouth, throat and gills of the Sand- 

 pike, Scmrus foetens. Beach Haven, N. J. 



24. Distomum lasium n. s. 



Larval form. Body fusiform, widest at the ventral disk, which is 

 situated near or a little in advance of the middle, finely annulate 

 and minutely echinate ; anterior extremity wider, rounded at the 

 end ; posterior extremity moderately tapering, truncate and emarg- 

 inate at the end. Ventral disk large ; oral disk nearly as large, 

 with a style inserted in the upper lip. Interior organs, except the 

 posterior contractile sac of the vascular system, indistinct. Sporo- 

 cyst. simple, elliptical with from few to numerous larval distomas. 



Larva 0'2 to 0"33 mm. long, by 0'08 to O'l mm. wide ; elongating 

 to 0"4 long by 0'04 mm. wide. Oral disk 0*048 mm. ; ventral disk 

 0-06 mm. ; style 0-016 mm. Sporocyst 0-375 by 0-15 mm. to 0-875 

 by 0-25 mm. 



Very common and numerous in the liver of Ilyanassa obsoleta, 

 Beach Haven, N. J. Ilyanassa oQCurs in great abundance at Beach 

 Haven, the mud flats of the neighboring sounds, at low tide, being 

 covered in dense patches. Covered with dirt, the ordinary observer 

 takes them for pebbles. In dissecting a number I found that about 



