INFUSOEIA 



53 



Key to the genera of Trachelinidae here described : 



o x Distinct neck region. 

 6 X Mouth runs the length of the neck. 



Ci Entire body uniformly ciliated 1. AMPHILEPTUS 



c 2 Ventral surface only ciliated 2. LIONOTUS 



&, Mouth at base of neck, which is very long 4. DILEPTUS 



a, No distinct neck region 3. LOXOPHYLLUM 



1. AMPHILEPTUS Ehrenberg. Body often curved, elongate, flattened, 

 with a sharp neck-like forward end; no gullet: 3 species; in fresh and 

 salt water. 



A. gutta Claparede (Fig. 80). Macronucleus double; length .08 mm. 



Fig. 81 



Fig. 80 Amphileptus gutia 

 (Conn) . Fig. 81 Lionotus fas- 

 ciola (Calkins). Fig. 82 Loxo- 

 phyllum rostratum (Conn). 



Fig. 80 



Fig. 82 



2. LIONOTUS Wrzesniowski. Body elongate, tapering to both ends, 

 with a large hump ; usually two macronuclei ; flattened side only ciliated ; 

 anterior end neck- like : 6 species ; in fresh and salt water. 



L. wrzesniowskii Kent. Length .18 mm. : in fresh water. 



L. fasciola (Ehrenberg) (Fig. 81). Body ellipsoid, hinder end 

 conical; length up to .6 mm.: in fresh and salt water; Woods Hole; Cold 

 Spring Harbor. 



3. LOXOPHYLLUM Dujardin. Body flat, with a broad hyaline border ; 

 anterior projection slight, turned to the right; trichocysts often in 

 papilla-like groups; nucleus often bead-like: in standing water; 4 

 species; in fresh and salt water. 



L. rostratum Cohn (Fig. 82). Body elongate; 

 length .15 mm. : in fresh water. 



L. setigerum Quennerstedt. Body broad; 1 

 mm. long: in salt water. 



4. DILEPTUS Dujardin. Body large, elongate, with a long contractile 

 neck, at the base of which is the mouth ; numerous contractile vacuoles ; 

 nucleus often bead-like : 2 species ; in fresh and salt water. 



D. anser (O. F. Miiller) (Fig. 83). Body striated; length up to 

 1.5 mm.: among algae in fresh water. 



Fig. 83 Dileptus anser 

 (Conn). 



