THE WHEEL ANIMALCULES (ROTATORIA) 597 



54 (55) Head shield broad, flat, appearing from above like a halo. 



Stephanops Ehrenberg. 

 Several species. 



Representative species (Fig. 899). . . Stephanops intermedius Burn. 



55 (54) Head shield arched, in side view appearing like a hook 56 



56 (57) Lorica arched and laterally compressed Colurus Ehrenberg. 



Many species. 



Representative species (Fig. 900) Colurus grallator Gosse. 



57 (56) Lorica flattened, wider than high Metopidia Ehrenberg. 



Representative species (Fig. 901). . . . Metopidia ehrenbergii Perty. 



58 (53) No head shield Cochleare Gosse. 



Lorica shaped like a coat, covering only the anterior half or less of the dorsal surface. One 

 or two species. 



Representative species (Fig. 902) Cochleare turbo Gosse. 



59 (52) Foot and toes usually long; if not, upper surface of lorica with long 

 spines Family DINOCHARIDAE . . 60 



Lorica entire, covering head as well as body. Movements often of a leaping character. 



60(63) Lorica without spines on dorsal surface. . 61 



61 (62) Lorica weak, hardly noticeable Scaridium Ehrenberg. 



No sculpturing of any sort; toes very long. Two species. 



Representative species (Fig. 903) . 



Scaridium longicaudum Ehrenberg. 



62 (61) Lorica rough Dinocharis Ehrenberg 



Two species. 



Representative species (Fig. 904). . Dinocharis pocillum Ehrenberg. 



