THE MANTLE -COVERED ANIMALS. 135 
And now that the sea-shore, the ponds, and the 
rivers are overrun with stomach-footed animals, there 
remains but the wide ocean. And even there they 
have made their way, for sailors in the Atlantic Ocean 
meet with the ocean-snail (lanthina), with its float 
of air-cells, floating in myriads over the sea and 
feeding on the small jelly-fish, and with the lovely 
Fig. 48. 
Oceanic Mollusca. 
I, lanthina, the ocean-snail, f, Foot ; r, raft of air-bubbles, with 
egg-bags hanging down. C, Carinaria. * f, Foot ; s, shell covering the 
breathing-gills, g ; both these forms float upside down. P, Pteropod 
or wing-footed snail. 
Carinaria, whose foot has been moulded into fins 
(f, C, Fig. 48) with which it swims upside down in the 
water, its delicate shell serving to protect its breath- 
* Carinaria atlantica. 
