EOTIFEEA 

 FAMILY 5. RATTULIDAE.* 



241 



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) (E. bicornis Ehrenberg) (Fig. 

 390). Two spines of unequal 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. DIUBELLA 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. Miiller) (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. lone; 



Diurella tigris , . . 



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



Fig. 390 

 Rattulus 

 longiseta 

 (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. lima (0. F. Miiller) (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. 



Fig. 392 



Cathypna luna 



(Siissw. F. Deut.). 



* 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. 



