222 AQUATIC MICROSCOPY FOR BEGINNERS. 



/. Eyes two, on the frontal column (proboscis) ; 

 toes three, the middle one small and -not easily 

 seen, Rdtifer, lo. 



g. Lorica with a visor-like projection in front, 

 Stephanops, ii. 



g. Lorica circular, flattened; foot long, cylindrical, 

 ■ retractile, Pterodina, 12. 



g. Lorica vase-shaped; foot long, with two exceed- 

 ingly long toes, Scaridium, 13. 



g. Lorica with 6, long, narrow, movable, oar-like 

 appendages on each side, Polydrthra, 14. 



g. Lorica with several tooth-like spines on the front 

 border, Brachidnus, 15. 



I. LacinulAria. 



The clusters contain numerous individual members 

 which secrete a common, soft, colorless,, or pale yel- 

 lowish, and short sheath with no special shape, this 

 formless jelly-like enclosure surrounding only the 

 posterior portion of the colony, where it must serve as 

 an exceedingly inefficacious protection, if it serve 

 any. 



The Rotifers themselves are somewhat trumpet- 

 shaped when extended, and to a certain extent resemble 

 Megalotrocha (Fig. 160). The ciliary disk is single 

 and horseshoe shaped. It is closed and drawn partly 

 into the body when the Rotifers retire intQ their 

 apology for a sheath, as they often do, the whole 

 colony continually waving and bobbing and bowing as 

 the members retire, or ascend to expand themselves, 

 the sheaths usually forming a little mass of jelly-like 

 substance, from all parts of which the Rotifers project. 

 The colonies are commonly adherent to Ceratophyllum 



