500 HARRY M. MILLER, JR., AND FLORA E. NORTHUP. 



CERCARIA DIPTEROCERCA sp. nov. 

 (Figs. 4, 5, 7, 8.) 



Distome larva with prominent lateral cuticular fins extending 

 along entire length of tail. Average body length 145 n, varying 

 between 109 fj. and 212 ju, width 50 /z, varying between 47 n and 

 65 /i. Body, but not tail, uniformly covered with small spines; 

 double row of large ones around mouth. Pigment present only 

 in two large eye spots, composed of very coarse granules and a 

 "lens." Oral sucker 24 ju in diameter, larger than ventral sucker; 

 subterminal mouth, prepharynx, pear-shaped pharynx; ceca not 

 seen posterior to ventral sucker. Nine pairs of three different 

 kinds of larval glands: on either side two pairs (Fig. 7, a), dorsal, 

 lateral to pharynx, with coarsely granular, yellowish cytoplasm; 

 stain with intra-vitam neutral red; eosinophilic in sections; 

 second group of four pairs (b), laterally situated, with finely 

 granular, greyish cytoplasm; basophilic with Ehrlich's acid 

 hematoxylin; third group of three pairs (c), not observed in 

 living cercaria; slightly basophilic in sections; no ducts found. 

 Large thick walled excretory vesicle, varying from elongate oval 

 to triangular in outline; main lateral collecting tubes and 

 positions of some flame cells shown. Reproductive system 

 represented by conspicuous mass of cells dorsal to ventral sucker. 

 Tail with a pair of lateral convoluted cuticular fins extending the 

 entire length ; smaller median fin on ventral side of distal fourth 

 of tail, extending around end up on to dorsal side; maximum 

 tail length 320 ju, average 250 /x. Development of cercaria within 

 elongate rediae, averaging 795 /z in length and 92 p in diameter; 

 pharynx large; more or less cylindrical redia constricted at 

 irregular intervals. 



Cercaria dipterocerca differs from C. hymenocerca Villot 1875, 

 C. quadripterygia Sinitsin 1911, and C. lophocerca (in Lebour, 

 1912) in significant details of structure. 



CERCARIA VARIGLANDIS spec. nov. 

 (Figs. 15-17-) 



Binoculate furcocercous distome cercaria most closely re- 

 sembling members of the Elvse group (Miller, 1923:44). Average 



