is variable can, with any consistency, be made use of to 

 express permanent distinctions, when not supported by 

 pecuharity of formation or sculpture. The great art in framing 

 the description of a species consists in singling out those cha- 

 racters alone which are most permanent, and exist in every 

 variety of that species ; for, when once a character is found 

 to be variable, it no longer becomes a distinction by which 

 a species can be recognised. I consider, therefore, forma- 

 tion and sculpture as the only certain characters of species, 

 and that variation of colour should alone distinguish 

 varieties. 



It is therefore not surprising that the specific characters 

 given by MM. Bruguiere and Lamarck, and resting princi- 

 pally on the colours of these shells, are frequently obscure, 

 and always long ; two inevitable evils attending every at- 

 tempt to describe minutely the colour, form, and disposition 

 of the markings of shells. In justice, however, to these 

 great naturalists, it should be observed, that in this attempt 

 they have done that best which no writer has ever done 

 well. 



The spire of C. generalis is generally spotted, and the 

 white band on the margin of the body whorl, more or less 

 crossed by broad waved stripes of a dark brown. It is an 

 inhabitant of many parts of the Indian Ocean. 



