'66 NATURAL HISTORY. 



BRANCHIAL SNAILS. 



First of this class is 



The Turbo (turbo scalaris), which is snow-white, 

 about two inches long, with shells having the whorls of 

 the spire so far apart that they touch only on the extreme 

 edge of the aperture ; this extremity is formed by the 

 border of the mantle, and completes the whole. The 

 spire is concave. This snail is a native of Ceylon, and 

 one hundred years ago was so rare, that a single one 

 would sell for five hundred florins, and at present the 

 usual price is ten florins. It is sometimes called Wen- 

 deltreppe or Winding Stair. 



A species of Turbo is found in the Mediterranean, 

 which, although resembling the genuine, is not the turbo 

 preciosa above described; the Avhorls of the spire are 

 closer together, which forms a distinguishing character- 

 istic. 



The Pagoda (turbo pagodus) is about two inches 

 long, the same in breadth, of a gray color, and furnished 

 with projecting ribs, which gives it a resemblance to a 

 Chinese roof. This snail can not live under water, but 

 hangs on rocks against which water dashes, and is so 

 tenacious of life, that it can live a year without food or 

 drink. Its only aliment is supposed to be the slime col- 

 lected on the rocks by the dashing of the spray. It is 

 found by all the streams in the East Indies : its flesh is 

 bad. 



The Giant's Ear or Oil Jar (turbo olearius) is two 

 hands' breadth in thickness, is rough and horny on the 

 outside, gray, spotted with green and brown. The shell 

 inside is like mother of pearl ; it adheres so closely to 



