PROTOZOA 



3. URONYCHIA Stein. Like Euplotes except that no anterior and 

 about 10 great anal bristles are present; movement rapid, with frequent 

 jumps: 2 species; marine. 



U. setigera Calkins (Fig. 116). Length .04 mm.: 

 common at Woods Hole. 



4. ASPIDISCA Ehrenberg. 

 Body oval with a short oral 

 groove in the middle of the 

 body and a short posterior 

 projection at the side of 

 body ; about 8 thick, anterior, 

 and 6, or more, anal bristles: 

 in fresh and salt water. 



A. hexaris Quennerstedt 

 (Fig. 117). Length .07 mm.; 

 6 anal bristles: Woods Hole. 



Fig. 116 



Fig. 117 



Fig. 116 Uronychia setigera (Calkins). 

 Fig. 117 Aspidisca hexaris (Calkins). 



ORDER 4. PERITEICHIDA. 



Cylindrical or cup-shaped infusorians in which the body is without 

 cilia except those forming the adoral zone at the oral groove, and in 

 a few cases a zone at the hinder end ; most of them are sessile : 3 families. 



Key to the families of Peritrichida here described: 



! Body attached by a broad sucking disc 1. LICHNOPHORIDAE 



a 2 Body usually attached by a slender stalk 2. VORTICELLIDAE 



FAMILY 1. LICHNOPHOEIDAE. 



Forward part of the body with an oval oral groove; the hinder 

 part stalk-like and broadened at the end to form a sucking disc 

 provided with a ring of cilia, by 

 which the animal fixes itself: 1 

 genus; marine; usually parasitic 

 on mollusks. 



LICHNOPHORA Claparede. 

 Characters given above. 



L. macfarlandi Stevens (Fig. 



Fig. 118 Lichnophora macfarlandi 

 (Calkins). 



118). Length .08 mm.; the animal 



moves about on its pedal disc: Woods Hole, on the egg capsules of 



Crepidula and on annelids. 



FAMILY 2. VOETICELLIDAE. 



Body cup-shaped and cylindrical and, with one or two exceptions, 

 attached by a stalk at the hinder end.; oral groove circular, around the 



