No. 415.] MORTH-AMERICAN INVERTEBRATES. 591 
bulbs ; otocysts alternating with bases of tentacles ; manubrium short and 
with four recurved oral lobes; gonads borne upon lower portions of canals. 
Manubrium, gonads, and sensory bulbs light greenish in color, Hydroid (?). 
Flalopsis ocellata A. Ag. 
Bell low and flat in mature specimens, though somewhat hemispherical 
in young medusz; radial canals twelve to twenty in mature specimens ; 
marginal tentacles very numerous and highly contractile, and with inter- 
spersed cirri; otocysts numerous and with numerous otoliths arranged in 
double rows; manubrium short, with four recurved sinuous oral lobes. 
Hydroid (?). 
(Condensed from description of A. Agassiz, VV. A. Acalephe, p. 99.) 
ff, cruciata A. Ag. 
Under this name A. Agassiz briefly describes a medusa having but-four 
radial canals, a hemispherical bell, comparatively few tentacles, and other- 
wise so unlike the preceding as to render its generic, if not family, affinities 
wholly distinct. Not having access to specimens, it is merely listed without 
further comment. Hydroid (?). 
Rhegmatodes tenuis A. Ag. (FIG. 58). 
Bell low, with rounded aboral surface and with margins distinctly incurved ; 
radial canals numerous, varying from twenty to forty or more in specimens 
examined; canals usually simple, but with many variations exhibiting con- 
necting branches and anastomoses ; 
marginal tentacles numerous, rather 
long and filiform, tapering rapidly 
from a somewhat broad base, above 
which is a tubular spur-like flap ; tenta- 
cles, like the radial canals, increase o£ 
with age, the larger extending from 
the termini of the canals, while inter- . 
mediate are smaller ones with still 
smaller intermediate tentacular rudi- 
ments; gonads suspended in double 
rows aleng the surface of the canals; 
manubrium extremely short, often in- 
distinguishable from the very shallow gastric pouch, and with its oral margin 
delicately crenulated ; otocysts numerous. 
In habit these medusz are rather sluggish, swimming or floating near the 
surface and rarely exerting more than two or three pulsations of the bell or 
small velum in succession. Hydroid (?). 
Fic. 58. — Rhegmatodes tenuis A. Ag. 
