TEOCHTJS. 31 



species known; they are mostly deep-sea shells found in warm 

 latitudes, although several inhabit the European seas, and one, 

 the Common False Wentletrap, {S. conwmm's,) Fig. 1, may 

 often be picked up on our own shores. Fig. 2, the Koyal 

 Staircase Wentletrap, is a rare and valuable shell, generally 

 brought from India and China; the scientific name is S. pretiosa, 

 given to it by the French Naturalist Lamarck, on account of 

 the high price which it fetched, pretiose, in Latin, meaning 

 costly, valuable. As much as £100 have been given for a 

 single specimen of this shell; and a fine one, especially if it 

 exceed two inches in length, yet commands a considerable sum, 

 although not nearly so much as that. A good deal like the 

 False Wentletrap in general outline, is the Awl-shaped Tur- 

 ritella, found in the African and Indian Seas. This is the 

 T. terehra of naturalists; the first name referring to the turret 

 shape common to the genus, and the last being the Latin 

 word for an auger, or piercer. The Eoseate Turritella, {T. 

 rosea,) is also sometimes seen in collections; the beautiful rosy 

 tint of the live shell changes to a dull red or brown, on the 

 death of the mollusk. 



TROCHUS, OR TOP- SHELL. 



"Of the shelled Mollusca which the dredge ever and anon 

 brings up," says Mr. Gosse, in his delightful volume on the 

 Aquarium, or Aqua-vivarium, as the glass tank in which 

 living marine animals and vegetables are kept, is called, from 

 the Latin aqua — water, and vivo — to live, ''the Trochi are among 

 the most conspicuous for beauty. The chief glory of this 

 genus is the richly-painted internal surface of their shells, in 

 which they are not excelled by any even of the true mar- 

 garitiferous or pearly bivalves." 



Of this Trochidce family, a few of the members must be 

 introduced to our readers; it is rather a numerous one, con- 

 sisting of more than one hundred species, which are scattered 

 nearly all over the world, few seas being without some of 

 them. They are found at various depths, from near the sur- 

 face to forty-five fathoms down, creeping on rocks, sand, masses 

 of sea- weed, etc. We will first speak of those found on our 



