to twenty-five in number, are gracefully rounded, and often marked 

 by many raised spiral lines. The aperture is about one-eighth the 

 length of the spire, which is long and tapering. 



Of all the Gastropods, none excel the curious Xenophora in point 

 of oddity. Its shell is in general form like that of the top shell, but 

 as it grows, it attaches to itself small 

 stones and pieces of shell so that 

 when the animal is fully grown it 

 looks like a heap of dead shells and 

 pebbles. This habit is, in all prob- 

 ability, for the purpose of concealing 

 itself from enemies. They are called 

 "carriers," and the individuals with 



i IT -i i ,1 i A carrier shell. Xenophora conchylio- 



shells attached to their houses are p h oruSt (Tryon.) 

 called conchologists, while those 



with stones so attached are called mineralogists. The fragments of shells 

 are attached with concave sides upward so as not to impede the progress 

 of the animal during locomotion. The carriers are not able to glide 

 as are other mollusks, as their foot is very small. They progress 

 by fixing the front part of the foot to an object, and then drawing the 

 hind part forward. In this way they jump and scramble along 

 in a ludicrous manner. 



Related to the "carriers" are the slipper shells (Crepidula) , the 

 horse-hoof shell (Hipponyx), and the bonnet limpet (Capulus). The 

 slipper shells are found in many parts of the world, and are particularly 

 abundant on the Atlantic and Pacific coasts of the United States. The 

 shell is flat and somewhat limpet-like, and across one end, near the apex, 

 is a little shelf, which gives the likeness to a Chinese slipper. They 

 adhere to stones, shells, crabs, and any submerged object, and modify the 

 form of their shell to fit the inequalities of their resting-place; thus, 

 a Crepidula on a pecten shell will be ribbed, while the same species 

 on a stone will be perfectly smooth. Frequently they may be seen piled 

 one upon another in tiers of six or more. Though the animal generally 

 feeds upon the seaweeds, it has been known to feed upon other mollusks. 

 The bonnet limpets also belong to this family, as do the cup and saucer 

 limpets (Cabjptrcea). Some of the bonnet limpets are believed never 

 to leave the spot to which they have become attached. 



We now come to a family noted for its blood-thirsty nature. 

 This is represented by the genus Natica, or the moon shell. The animal 

 is quick in movement as it plows its way through the sand with 

 its enormous foot, in search of bivalves. When one is found, the radula 



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