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POPULAR CONCHOLOGT. 



Philippi observes that this genus is founded on Bulla 

 hydatis and its allied species. 



Glauconella. Gray. ( Thecaphor us NutalL) — Shell 

 very irregular, oval, scarcely rolled even at the spire. 

 Animal, with a quadrate head-shield, which bears above 

 it the two eyes ; no tentacula, and no processes directed 

 behind; the foot tolerably large; the mantle extended 

 on each side into two large wings, which can be thrown 

 back over the shell. — Few species. 



This genus is formed on Bulla viridis of Quoy and 

 Gaimard, B. glauca, and some others. 



Cryptophthalmus. Ehrenburg. — Shell fragile, horny, 

 very slightly rolled in ; no columella nor spire ; aperture 

 wide. Animal, with the head-shield small, deeply bor- 

 dered behind, without any indication of tentacula, and 

 bearing the eyes sideways ; the foot very large, both sides 

 (like Atys) extended into wings, which are thrown back 

 over the shell. — 1 species. 



C. smaragdinus of Ehrenburg. 



Xanthonella. Gray. — Shell small, more resembling 

 an Aplysia than a Bulla, longish, oval, the outer part 

 convex, the inner concave, lengthened behind into a beak, 

 furnished at the right side with a slight roll inwards, 

 which supplies the place of a spire. Animal, with a small, 

 almost quadrate head bordered behind, and bearing the 

 eyes; the foot rather long, far larger than the shell; 

 the mantle drawn out on each side into a wing-shaped 

 lobe, which may be drawn over the back. 



Bulla lutea of Quoy and Gaimard forms this genus. 



Alicula. Ehrenburg. — Shell not appearing to differ 

 essentially from Bulla. Animal, cylindrical, head-shield 

 rhombic, bearing the eyes sideways ; the foot three- 



