THE WHEEL ANIMALCULES (ROTATORIA) 603 



79 (78) Lorica longitudinally striated Nothoka Gosse. 



Sometimes very long and slender. Three or four species. 



Representative species (Fig. 916). . . N otkolca longispina Kdhcott. 



80 (77) Lorica with long bristle-like outgrowths from its surface but not 

 from anterior or posterior borders Eretmia Gosse. 



Few species, all more or less doubtful. 



Representative species (Fig. 914) Eretmia trithrix Gosse. 



81 (74) Foot present 8a 



82 (85) Foot projects from ventral surface 83 



83 (84) Lorica entire, not wrinkled Family Gastropodidae. 



Lorica flask-shaped with small foot projecting from ventral surface. Foot ringed, ending 

 in one or two toes. 



One genus only Gastropus Imhof. 



Several species. 



Representative species (Fig. 915). . Gastropus hyptopus 'Ehrenb&cg. 

 (Fig. 917) G. stylifer IroLhoi. 



84 (83) Lorica open along mid-ventral line; marked with wrinkles or vesi- 

 cles Family Ploesomidae. 



Lorica stout, widely open in front for the large head, and open ventrally for the foot. Foot 

 strong, ringed, ending in two toes. Strong, active rotifers. 



Only one genus Ploesoma Herrick. 



Three or four species. 



Representative species (Fig. 920). . Ploesoma truncatum Levander. 



(Fig. 918) P. lenticulare Herrick. 



(Fig. 919) P. hudsonihuhot. 



