SOME SNAILS OF THE OCEAN. 



The Marine snails outnumber all of 

 the other mollusks and their shells are 

 far more beautiful, those in the tropics 

 having the most gaudy colors imagin- 

 able. The animals are all formed on the 

 same plan although each family has 

 some peculiarity not shared by its rela- 

 tives. They are found in all parts of 

 the world, and in all climates. While 

 the majority of species live either be- 

 tween tides on near low water, there are 

 not a few which live in the abysses of the 

 ocean and have been dredged at a depth 

 of three thousand fathoms, a distance 

 of over three miles. The average depth 

 at which mollusks are found in any num- 

 ber is about one thousand fathoms. The 

 variability of marine snails is so great 

 that only a few typical forms can be 

 mentioned. 



The Limpet or Patella is a familiar 

 mollusk to many visitors at the sea 

 shore. This shell is a depressed, conical, 

 oval disk, looking not unlike a miniature 

 shield. They live on rocks, to which 

 they tenaciously cling. Some experi- 

 ments which were made on the English 

 limpet several years ago showed that 

 they could sustain a weight of thirty 

 pounds attached to their shell without 

 being pulled from the rock. The ani- 

 mal seems to have a pretty clear idea of 

 local geography, for it invariably re- 

 turns to the same place after its excur- 

 sions for food and the rock in some lo- 

 calities has been hollowed out to a con- 

 siderable depth by the continuous dwell- 

 ing thereon of the limpet. If the sur- 

 face of the rock is uneven the shell 

 grows in such a manner as to fit these 

 inequalities. While grazing along the 

 sides of a rock covered with fine sea 

 weed it will leave a track like a worm 

 and will clear off quite an area in a very 

 short space of time. This track is made 

 by the radula, which is very long and is 

 thrust out and loaded with food which it 

 carries to the mouth. When at rest the 

 radula is coiled like a watch spring. On 

 the British coast the limpet is used as 

 an article of food and primitive man 

 not only ate the mollusks but made a 



necklace by stringing the shells together. 

 There are several hundred species of 

 limpet-like shells and they are found in 

 all parts of the world, especially on 

 rocky shores. 



A family of shells closely related to 

 the limpets is the Fissurellidae, or key- 

 hole limpet, distinguished from the last 

 family by having a slit or foramen in 

 the apex of the shell, through which the 

 waste products of digestion are dis- 

 charged. This slit resembles a key-hole 

 and for this reason they are called key- 

 hole limpets. The shells of Fissurella 

 are generally rougher than those of Pa- 

 tella and they live, as a rule, in warmer 

 seas. In habits the key-hole limpet re- 

 sembles the limpet, living in one rocky 

 place and making excursions for food. 

 In the young shell the spire is without 

 a perforation, this appearing as the shell 

 increases in age. There are over one 

 hundred species of key-hole limpets, sev- 

 eral handsome species of which inhabit 

 Florida and the West Indies. 



The Haliotis or abalone shells abound 

 in many parts of the world and are 

 widely known for their beauty. The 

 largest and finest shells live on the coast 

 of California where they attain a length 

 of ten inches. The shells are flat, though 

 made in the form of a spiral and are 

 perforated near the edge of the last 

 whorl, which is many times the size of 

 all the rest combined, and through this 

 perforation the water from the gills, to- 

 gether with the waste products of the 

 animal, are poured out. As the shell in- 

 creases in size the old holes are filled up 

 'and new ones are formed. The inside 

 of the shell is resplendent with iridescent 

 colors, particularly about the region of 

 the huge muscle scar, and when the out- 

 side is polished they become objects fit 

 for the palace of a king. A large part 

 of the mother-of-pearl is furnished by 

 these shells and a vast number are an- 

 nually exported for the purpose of mak- 

 ing pearl buttons. In England they are 

 called "Ormers" but the correct name, 

 if we translate the generic title, is "Sea- 

 ear" or ear-shells. To the Chinese the 



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