338 THE AMERICAN NATURALIST. [Vou. XXXVII. 
Family CyANEID#. Radial canals broad and pouch-like, and with 
numerous ramifying, blind, lobular canals; no circular canal; 8-16, rarely 
more, marginal lobes. 
Family PELAGID#. Radial canals rather broad but simple and without 
ramifying branches ; no marginal canal; usually 16 marginal lobes. 
Sub-order 3. RHIZOSTOM. 
Discomeduse in which the mouth early becomes more or less overgrown 
and obliterated by the 8 root-like oral arms; gastric cavity extending into 
the oral arms and opening by funnellike mouths on the edges and sur- 
faces. Devoid of marginal tentacles. 
Family ToREUMID&. Radial canals 8-16, narrow and with anastomos- 
ing branches; devoid of marginal canal; rhopalia 8-16. Suctorial fun- 
nels on the outer (dorsal) surface of the oral arms. 
Family PILeEMIp#. Radial canals 8-16, occasionally more, variously 
branching and anastomosing; rhopalia 8. Suctorial funnels on both outer 
and inner surfaces (dorsal and ventral), of the oral arms. 
KEY TO THE GENERA. 
EPHYRID. 
1. Gonads four, simple, horse-shoe-shaped ; devoid of marginal lobes or 
lobular pouches . . . ; Boot aver oo) oe oe ode Ep aihe 
2. Gonads 4, Lobular nouches iG 8 ocular, 8 tentacular, Bathyluca. 
3. Gonads 8, symmetrically disposed; 16 lobular pouches, ocular, 
Nausithoé. 
4. Gonads 8, symmetrically disposed ; 32 lobular pouches, 16 ocular, 16 
tentaculan: 2 3 ie Ls eee) Be eee eee eee Nauphanita: 
5. Gonads 8, arranged in pairs; lobular pouches 64-128, number indefi- 
MAGS, CEA k sak ese ar pe Sy Rete I ek ears roc 1 acc me EO Lea 
6. Gonads 4, two-lobed, with interradial septum . . . . .  Linerges. 
ULMARID. 
Rhopalia 8; tentacles numerous, short, borne on under margin of the 
umbrella without the velar lappets; oral arms 4, simple but with the 
margins fringed with nematocysts, . . . i Aeon Aurelia. 
8. Rhopalia 16; tentacles numerous, long, in ‘e meee s on the lower mar- 
gin within the velar‘lappets . . . : .. . . . ., Phacellophora. 
“I 
CYANEIDE. 
9g. Rhopalia 8; tentacles very numerous, long, arranged in 8 clusters, 
each comprising several rows. Oral lobes four, but highly folded and 
fringediac "Rye 2 il Si 5 A rene 6 eee aU ee Summer 
