90 THE AMERICAN MONTHLY [May 
** Lobe single, frontal, arched ; setz none ; foot truncate..Acyclus, 2 
***T obe a single, frontal, membranous cup; foot none........ Apsilus, 3 
§[§] Corona two circular, transverse lobes, (a) 
§/§| Corona a flat, ventral, ciliated surface, (b) 
a Byes: 2;: cervioal oie yk ie Es Se a Pa a Philodina, 13 
a Eyes 2, within the frontal column... 0... VE OER: Rotifer, 14 
a Eyes 2, frontal; body exceedingly long and slender. Actinurus, 15 
a Eyes none; body slender, pointed Callidina, 16 
b Eyes none; body smooth, furrowed; teeth 2.000000... Adineta, 17 
c Illoricate ; foot, when present, not transversely wrinkled, (d) 
c Loricate, wholly or partly ; foot various or none, (t) 
d Body without skipping appendages, (f) 
d Body with skipping appendages, (e) 
e Spines in clusters on the shoulders....... Polyarthra, 22 
e Spines single, 2 lateral, 1 ventral. Triarthra, 24 
e Spines (styles) 2, on the breast... ooo ecco cccceessceesees eee . Pedetes, 25 
f Corona with styligerous prominences, (g) 
f Corona without styligerous prominences, (4) 
g Ciliated auricles 2; body usually obconical; mastax large 
BURA US SO VRT eldee SURG NAMBU RDC Ue yor by hh A Syncheta, 21 
g Ciliated auricles none; corona truncate, (h) 
gz "a: . ‘¢ corona transverse, mastax and eye 
TT 4 RRA ARENT SAT SVE Scheel ose TCE be ER Yo ey Polyarthra, 22 
h Corona without proboscis, (i) 
i Eye1l, occipital; body not conical; foot retractile..._... Notops, 28 
i », 1, cervical; body conical; foot not retractile 
PSE TARIARMIION CRM LISS Nae ONE (Cyrtonia*), Notommata, 32 
i Eye none; body obconical Ale Hydatina, 26 
i Eye none; body not conical; 2 dorsal, 2 ventral antenne ; 
FOGt  VOCPACHHIE os Ek Ce aE Ce ah ccs converts Dinops, 78 
j Foot absent, (k) 
j Foot furcate, ventral, retractile, (1) 
j “$0 or not ventral; corona without proboscis, (m) 
j " 4“ corona with dorsal proboscis bearing 2 eyes 
SR RNE OWN A BOUIN U LY RPE NO TSA TEA De, Siete EEN Rhinops, 28 
j Foot stylate ; brain and eye purple... o... Microcodon, 18 
j ¥F 2 with a apur seve red foe Microcodides, 79 
j Foot present, toe 1. Vermiform, entoparasitic............ Albertia, 29 
k Corona subconical, with 2 apices. Viviparous...... Asplanchna, 19 
k 
1 
* rib with 1 apex; body sack-like.......... Sacculus, 20 
Body subcylindrical, dorsum gibbous : trophi forcipate 
dine: hddalioeblagas ety Gee mane Gd 3 GU ale ae ea Triphyllus, 68 
1 Body not subcylindrical; no humps; rami curved, smooth 
sities hg vc Lagcbdading tc paeoases at ie WML ake Asplanchnopus, 67 
m Body more or -less cylindrical, (n) 
* Journal Quekett Micros. Club, 1894, 433, 
