(iASTKOroi)A. 



19 



arc found floating about in every ocean, with the spire of the shell 

 downwards, and the bottom, being more exposed to the action 

 light, is more deeply tinted than the upper part. They 1'eed upon 

 Jelly-fish, and construct a gelatinous raft, tilled with air-bubbles, 

 beneath which the females attach their eggs. 



A large section of the Gastropods, commencing with the " Apple- [Cases 

 Snails" (Ampullariida) and ending with the "Carrier-shells" oh-9b 

 (Plioridce), are mostly vegetable-feeders, and, unlike the preceding 

 families, have a proboscis or snout, which is not retractile. 



The "Apple-Snails" (Ampullariidai) live in the rivers and [Cae 

 marshes of tropical regions, and, although represented by a large ,; " ' x ■ 

 number of species, exhibit comparatively slight variations in form 

 and colour. 



Of the Ovulidce, the most curious is the "Weavers-shuttle" Case 7b.] 

 [Radius volva), in which the shell is peculiarly beaked at both 

 ends. It is found living on barked corals (Gortjonildce), and some 

 of the smaller species exhibit differences of coloration, resembli 

 the tints of the Gorgonias upon which they arc found. 



The "Cowry-shells" (Cyprteidce) are remarkable for their 



ise 7, 



i:-K.J 



Fig. 9. 





J 



<J < 



The Tiger Cowry (Cypreea tigris). (From the Indo-Paciflc Ocean.) 



a, the shell; b. the mantle; c, foot; d, siphon; e, prohoscis; /, tent. 



!/, eyes. 



varied markings and splendid polish, which is produced aud 

 preserved by two flaps of the mantle, one on each side, which 

 fold over the back, a line down the centre of which usually marks 



