114 



CHAPTER XXVIII. 



OP THE STROMBUS. GENUS XXV. 



STROMBUS. 



'•Animal a Limax. Shell univalve, spiral, side enlarged; aperture, lip 

 often dilated, ending in a canal to the left." — Li\n. 



Phe essential character of this genus is an obtuse indent or 

 hollow on tlie margin of the outer lip, near to the canal which 

 terminates the aperture ; this additional hollow is to the left 

 when the shell is placed with the mouth upwards, and conse- 

 quently if placed in its natural position it is on the right. 



These are commonly thick strong shells, and many of them 

 are defended by a kind of horns or claws, which extend in 

 various directions from the edge or margin of the outer lip, 

 when they come to their full growth : the form of the mouth 

 is various ; in some it is very small in proportion to the whole 

 shell, as in S. Pes pelecani; it is sometimes toothed on one 

 or both sides, as in S. Scorpius ; some liave the mouth very 

 large, with smooth lips, as S, Crigas: this genus is clearly 

 distinguished by the additional hollow on the margin of the 

 outer lip. 



Linnaeus makes four divisions ; the first called Digitati, the 

 second Lobati, the third Ampliati, and the fourth Turriti. 



