ROTIFERA. 



109 



2. Body partially enclosed in a shell. 



Monura (Ehr.) . Body compressed ; shell bivalve ; 

 head armed with a moveable hook; two eyes in 

 the front ; foot single-toed. 



M. coluris. Fig. 185 ; mag. i-f . 



Colurus (Ehr.). As Monura, except that the 

 foot is two-toed. 



C. uncinatus. 



caudatus. Fig. 186; mag. ijo. 



183 



Brachionus (Pallas). Shell somewhat three- 

 sided, spinous in front, rounded behind; a long, 

 very flexible foot ending in two small toes ; one 

 large eye in the midst of the thorax. 



B. Miilleri. Fig. 187 ; mag. ] -f . 



Pterodina (Ehr.). Shell much depressed, rounded 

 all sides; a long flexible foot without toes, 

 iated at the tip ; two eyes in front. 



P. clypeata. Fig. 188; mag. 1 ^. 



