MEDUSID. 165 
like tentacles, of a bright red. The peduncle is broad and flat, 
perforated in the middle, to which are attached four broad foliaceous 
arms. Cyanea aurita is figured on page 160. 
Fig. 56.—Rhizostoma Aldrovandi. 
In the genus &izostoma the disc is hemispherically festooned, 
depressed, without marginal tentacles, peduncle divided into four 
pairs of arms, forked, and divided almost indefinitely each having at 
their base two toothed auricles. Such is RAczostoma Cuvierit of Péron 
(Fig. 55), the disc of which is of a bluish-white, like the arms, and of 
a rich violet over its circumference. This beautiful form is found 
