The Agate Shells 



where it is protected from the sun. On the mainland it grows 

 larger than on the islands and the shell is thicker. Themollusk 

 is omnivorous, eating when kept in captivity, meat, vegetables, 

 dead snails — even pieces of old newspaper. One laid, in a 

 snailery, two hundred small eggs. 



The dry season drives them all into holes in rocks and trees. 

 They often congregate, a dozen or more in one pocket. The shell 

 is sealed with an opaque, papery epiphragm. Length, 2 to 4 

 inches. Mozambique and African coast. 



Genus STENOGYRA, Shuttl. 



Shell long, turreted, white or transparent; whorls many, 

 delicate; aperture oval; lip simple, sharp. Two hundred and 

 fifty species in tropical and temperate countries. 



The Obelisk Stenogyra (S. obeliscus, Moric), is a handsome, 

 yellowish, auger-shaped shell, the last whorl about one-quarter 

 the total length. Length, 3 to 4 inches. Width, | inch. 



Habitat. — Tropical America, Natal, Philippines. 



The Limy Stenogyra (5. calcarea, Born.) shows its calcareous 

 substance by the scaling off of the chestnut brown epidermis. 

 But little longer than 5. obeliscus, it is much larger, its basal 

 diameter is sometimes i J inches. Brazil. 



S. decoUatus, Linn., smooth, delicate, of pale livid hue, well 

 illustrates the peculiar habit of building partition walls, and then 

 dropping off the shell apex, by degrees. Moquin-Tandon reports 

 that the mollusk jerks the shell against some hard object to break 

 it off. The average specimen has four or five whorls remaining. 

 This European species is established at Charleston, S. C. Length, 

 I to I i inches. 



THE LITTLE AGATE SHELLS 



Family Achatinellid^e 



Shell small, conical, dextral or sinistral, solid; columella 

 plaited, lip thickened within the aperture. 



Genus ACHATINELLA, Swains. 



Shell smooth, whorls six or seven, banded and spotted with 

 bright colours; columella short, callous, or toothed, often twisted; 



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