i6 



phores, and a shell of over lapping plates bearing long spines ; Euglena 

 (fig. 6) and Phacus (fig. ii), both green in color and with red eye, the 

 former with flexible body, the latter rigid. 



ROTIFERA.* 



a. Jaws raniate (fig. lo), lateral palpi wanting; not fixed when adult, not 

 forming colonies, rarely living in tubes ; body ringed transversely ; 

 head and foot telescopic retractile ; no armor ; swimming with the 

 corona and creeping like a leech by the help of proboscis and foot ; a 

 proboscis, sometimes small, behind the corona. Two ovaries. 



DIGONONTA. BDELLOIDEA. 

 b. Corona of two circular retractile lobes. Philodinid^. 



c. Eyes present, 

 d. Eyes in the neck, just above the jaws (fig. i). Philodina. 



dd. Eyes on the proboscis (figs. 2, 3). Rotifer. 



cc. Eyes absent. Ca/lidina. 



bb. Corona a flat ventral ciliated disk. (fig. 4). Adinetid.^. Adineta. 

 aa. Jaws never ramate, lateral palpi always present, though sometimes 

 indistinct, head and foot not telescopic retractile ; movement not 

 leech-like nor inch-worm like ; not fixed, no dorsal proboscis behind 

 the corona. One ovary. MONOGONONTA. 



b. Adult animals attached or united in colonies, usually dwelling in tubes, 

 or if separate and free swimming then carrying the transparent tube 

 with them ; foot ending in a flat disk or cup, which is attached to the 

 substratum or to the bottom of the tube (or foot absent) ; free swim- 

 ming when youug. RHIZOTA. 

 c. Corona with long setae or conspicuous moving cilia, or both, 

 d. Corona with long slender sette and usually produced into a varying 

 number of tubes bearing the setae ; mouth in the center of the large 

 corona ; cilia few, about the mouth scarcely noticeable ; jaws 

 uncinate ; not forming colonies. Floscui,arid.'IC. 

 e. Setae not arranged in whorls or parallel rows on the lobes of the 

 corona, but scattered, or in groups (fig. 5). Floscularia. 

 ee. Setae arranged in whorls or oblique parallel rows on the 5 long 

 pointed lobes of the corona (fig. 6). Step/ianoceros. 

 dd. Corona without setae and not produced into long lobes, but with 

 strong conspicuous moving cilia forming a marginal continuous 

 curve on the dorsal side ; mouth near the ventral side of the 

 corona ; on the body just below the corona either a single dorsal 

 antenna or two ventral ones or all three are noticeable ; jaws 

 malleo- ramate (fig. 11). Melicertid.^. 

 e. In clusters of usually many individuals, frequently forming a 

 spherical colony, 

 f . Clusters attached. 



g. Body with 2 or 4 opaque warts in a transverse row on the ventral 

 side ; no tube ; corona broad, kidney shaped ; with short axis 

 dorso-ventral, antenna; inconspicuous. Megalotrocha. 



* Adapted from keys given by Jennings, Collin, et al. 



