64 



PROTOZOA 



3. Uronychia Stein. Like FAtplolrs except that no anterior and 

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

 jumps: 2 speeies; marine. 



U. setigera Calkins (Fiji". 110). 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.; 

 G anal bristles: Woods Hole. 



Fig. 116 



Fig. 11- 



Fig. 116- 

 Mg. 117 



-Uronychia setigera (Calkins). 

 —Aspidisca hexaris (Calkins). 



Order 4. PERITRICHIDA. 



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

 cilia except those forming the adoral zone at the oral groove, aijd 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: 



tti Body attached by a broad suckmj? disc 1. Lictinophoridae 



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



Family 1. LICHNOPHOEIDAE. 



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

 I)art stalk-like and broadened at the end to form a sucking disc 

 piovided with a ring of cilia, by 

 which the animal fixes itself: 1 

 genus; marine; usually parasitic 

 on mollusks. 



LiCHNOPHORA Claparede. 

 ( Iiaracters given above. 



L. macfarlandi Stevens (Fig. 

 lis). Length .08 mm.; the animal 



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

 Crepidula and on annelids. 



Family 2. VOKTICELLIDAE. 



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

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



Fig. 118 — Lichnophora macfarlandi 

 (Calkins). 



