CRASS ATELLA. 349 



tions^ though retaining their original formation, become 

 pressed up to the iimboes. 



The C. castanea, or Chestnut Crassatella, the largest of 

 the genus, is singularly distinguished by a smooth erosion 

 of the umboes, as also by the bright horny nature of the 

 epidermis. Three specimens of this fine shell are the pro- 

 duction of New Holland, each exhibiting a marked pecu- 

 liarity of character. 



The magnificent Crassatella of the West Indies [C. Antil- 

 larum), di'edged at the island of Margaretta, in the pearl- 

 fisheries, has the same rich chocolate-coloured interior as the 

 C. undulata, to which species it approaches nearer in most 

 respects than any other. 



The Sunbeam Crassatella [C.jiibar), from the western 

 coast of New Holland, is also deserving of especial notice. 

 It exhibits a great peculiarity of character, in being so 

 richly illumined with rays, as to deserve the name it bears. 

 A solid triangular form, and bright warm rose-colour, de- 

 signate the pretty little Three-cornered Crassatella {C. tri- 

 qiietra), of which the habitat is unknown ; a peculiar singu- 

 larity in the strise, the Contrarily-striated Crassatella [C.di- 

 varicata), from the coast of Guinea. In this species, 

 the anterior half of the shell is marked transversely, the 

 posterior obliquely. 



