CHAP. XXVIII. 



UNIVALVES- 

 STROM BUS; Winged, or Clatv Shell. 



Q. WILL you describe the Strombus? 



A. This shell is spiral, aperture much dilated, 

 lip expanded, and ending in a canal inclined 

 towards the left, or from the columella. 



Q. Are these the only peculiarities ? 



A. No, a very striking one is the sinus, a deep 

 cut in the outer lip, which is situated near the 

 base, but is not at all connected with the channel 

 of the rostrum or beak. This generally furnishes 

 a better discriminative mark than the direction 

 of the beak, which is not always evident. It 

 must, however, be remarked, that several species 

 do not possess the sinus, which are apparently 

 Strombi, from the obliquity of the canal ; but 

 as this conformation is not found in any but a 

 Strombus, it is a sure criterion of the genus 

 where it does exist. 



