60 



PROTOZOA 



S. polymorphus (0. F. Miiller). Body usually green from the pres- 

 ence of algae (zoochlorellae) but sometimes colorless; length 1 mm.: 

 sometimes very abundant on water plants. 



S. rceseli Ehr. Body colorless; nucleus ribbon-shaped; often 

 attached by a short case; length 1 mm. 



FAMILY 4. HALTERIIDAE. 



Body spherical or ovoid, often with long bristles and a few cilia 

 scattered over the body; animal moves by springing: 2 genera. 



1. HALTERIA Dujardin. Body small, spherical, 

 with anterior adoral ciliated zone, and usually body 

 bristles: 2 species; in fresh water. 



H. grandinella (0. F. Miiller) (Fig. 104). 

 Length .04 mm. 



2. STROMBIDITJM Claparede and Lachmann. Like 



Fig. 104Halteria Halteria, but without the bristles: 6 species; in 

 grandinella (Broun). fregh and ^ water 



S. caudatum Fromentel. Caudal appendage present; length .035 

 mm.: in fresh and salt water. 



FAMILY 5. TINTINNIDAE. 



Body attached by a stalk to a cup: 5 genera. 



1. TINTINNOPSIS Stein. Animal in a chitinous 

 cup on which are embedded sand granules; anterior 

 end has two circles of cilia: numerous species; 

 marine. 



T. beroidea St. (Fig. 105). Cup thimble-shaped; 

 length .05 mm.: Woods Hole. 



T. davidom Daday. Cup elongate with a long 

 spine; length .23 mm. 



2. TINTINNUS Ehrenberg. Like Tintinnopsis 

 except that no sand grains are imbedded in the cup : 

 numerous species; in fresh and salt water. 



T. amphora Claparede and Lachmann. Length .1 mm.; cup elon- 

 gate: marine; Cold Spring Harbor. 



Fig. 105 Tintin- 

 nopsis beroidea 

 (Calkins). 



ORDER 3. HYPOTRICHIDA. 



Body flattened and with cilia, spines, cirri, and membranelles 

 confined to the ventral surface; dorsal surface may have bristles: 3 

 families. 



