ROTIFERA 



241 



Family 5. RATTULIDAE. 



The very short foot ends in one or more slender, often very long, 

 bristle-like toes; lorica more or less cylindrical; 1 eye: 2 genera and 

 35 species. 



1. Rattulus Lamarck. One long toe, often as long as 

 the rest of the body; a short toe also usually present which 

 is not a third the length of the long toe: 20 species. 



R. longiseta (Schrank) {R. hicornis Ehrenberg) (Fig. 

 390). Two spines of imequal length at the anterior margin 

 of the lorica; toe two-thirds the length of the body; length 

 .5 mm.: common. 



R. mucosus Stokes. Lorica with 2 parallel ridges close 

 together for half its length ; body ovoid : length .2 mm. : often 

 common. 



2. DiURELLA Bory de St. Vincent. Two toes present of equal 

 length or one more than a third the length of the other: 

 14 species. 



D. tigris (0. F. Mliller) (Fig. 391). Toes equal and 

 long; body cylindrical, .2 mm. long with a tooth on 

 anterior margin of the lorica: very common in aquatic 

 vegetation in quiet water. 



D. porcellus (Gosse). Toes slightly unequal, folded 

 Fig. 391 under the body, which is short, curved, and .15 mm. long; 



DiureUa tigris -^i o • i j. xi 



(Jennings). lorica with 2 marginal teeth: very common. 



Fig. 390 

 Rattulus 

 lotK/iseta 

 ( Siissw. F, 



Deut.). 



Family 6. CATHYPNIDAE. 



Body broad; dorsal plate convex, ventral plate flat, the 2 plates sep- 

 arated by a deep groove on each side; foot very short with 1 or 2 rod- 

 shaped toes; 1 eye: 3 genera. 



1. Cathypna Gosse. Lorica oval or nearly 

 circular ; 2 toes : 3 species. 



C. ungulata Gosse. Body large^ being .3 mm. 

 long, including toes; dorsal plate projecting over the 

 foot; toes half as long as lorica: often very common. 



C. luna (0. F. Mliller) (Fig. 392). Toes two- 

 fifths as long as lorica; each with a distinct shoulder at side near the 

 tip; length .2 mm.: often common. 



2. MONOSTYLA Ehrenberg. Body oval or nearly circular, with 1 

 rod-like toe: 10 species. 



* See "The Rotatoria of the United States, II ; a Monograph of the Rattulidae," 

 by H. S. Jennings, Bull. U. S. Fish. Com., Vol. 22, p. 273, 1903. 



Fig. 392 



Cathypna luna 



(Siissw. F. Deut.). 



