444 



THE OCEAN WOKLD. 



These little creatures, so inoffensive, and which live together in vast 

 numbers, seem to be an easy and ready-prepared prey, which the 

 great marine animals may swallow by thousands. Twenty species of 

 Hyalea are described as actually living in the Atlantic and Australian 

 seas. Of these Hyalea gibbosa (Figs. 305, 306) and Hyalea longi- 

 rostris (Figs. 307, 308) are here represented. 



The great flappers of Hyalea tridentata are yellow, marked at their 

 base with a fine violet spot. Its shell, plain above, convex beneath, 



Fig. 309. Cleodora lanceolata (Lesueur). 



Fig. 310. Cleodora compressa (Ej'doux 

 and Souleyet). 



is cloven on the side. The superior part is longer than the inferior, 

 and the transverse line which unites them is furnished with three 

 teeth. This shell is yellow, and nearly translucent. "When the 

 animal swims, two expansions of its mantle issue 

 from the lateral clefts in the shell. 



Cleodora lanceolata is a delicate and graceful 

 creature ; its body, of gelatinous appearance, has 

 a distinct head, with its fins near the neck, 

 notched in the form of a heart (Fig. 309) ; its 

 ciwdora ouspidata posterior part is globulous, transparent, and lumi- 

 nous even in the dark. The animal which in- 

 habits it sometimes shines through the shell like a light placed inside 

 a lantern. This shell is triangular, as in Cleodora cuspidata (Fig. 

 311), thin, vitreous, and fragile, terminating in a long spine at the 

 base. 



Fig. 311. 



