2^6 RRSEARCHKS IN HELMINTHOLOGY AND PARASITOLOGY. 



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 mm. ; 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 ca?cal extremity. From the Skip- 

 jack, Thc/iiunis lepturus. 



23. Distojtium ischnum, n. s. — Body long, narrow, band-like with 

 the ventral disk at the anterior fourth ; smooth, translucent, brown- 

 ish with lateral black lines due to the long, tortuous, and sacculated 

 forks of the intestine : anterior extremity slightly narrower, with 

 rounded head and unarmed : posterior extremity transversely corru- 

 gated, 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 "i'"- Ova 

 0.02 by 0.012 mm. 



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

 pike, Sannis fa:iens. Beach Haven, N. J. 



24. Distomum lasitim , n. s. — Larval form. Body fusiform, widest 

 at the ventral disk, which is situated near or a little in advance of 

 the middle, finely annulated and minutely echinate ; anterior ex- 

 tremity wider, rounded at the end : posterior extremity moderately 

 tapering, truncate and emarginate 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. Sporocyst simple, elliptical with from few to 

 numerous larval distomas. 



Larva 0.2 to 0.33 mm. long by 0.08 to o. i mm. wide ; elongating 

 to 0.4 long by 0.04 mm. wide. Oral disk 0.048 mm.; ventral di.sk 

 0.06 mm.; style 0.016 mm. vSporocyst 0.375 by 0.15 mm. to 0.875 

 by 0.25 mm. 



Very common and numerous in the liver of //vaiiassa obsolcta. 

 Beach Haven, N. J. /lyanassa occurs in great abundance at Beach 

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

 covered in den.se patches. Covered with dirt, the ordinary observer 

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

 one in five or six was infested with the larval di.stonias enclosed in 

 sporocysts, often in large numbers, embedded in the liver and asso- 

 ciated genital gland. The larvae always appear in the distoma form 

 and never as a cercaria. They exhibit no trace of genital organs. 



