UNIVALVES. 



PLATE XXXV. 



Genus. CERITHIUM. 



Character. Shell turreted ; the opening oblique, and ending at the base in a 

 channel cut short by a sudden recurvature ; lip ending at the top in a distant chan- 

 nel ; mouth labiated all round ; spire long, and irregularly bulbous. 



Species. 



No. 1. Cerithium despectum. Shell of a pale brown, the folds of the spire ca- 

 runculated, unequally and irregularly ; mouth white, inclining to purple ; 

 the general form of the spire bulbous and pyramidal. A lately discovered 

 shell, from the South Seas. Delineated from one in the Author's Museum. 



No. 2. Cerithium curvirostra. Shell white, streaked crosswise with brown 

 shades ; spire very tuberculous ; mouth of a rugged form, and divaricated ; 

 the cheek ending in a pointed beak, crossing over the front of the mouth, 

 from whence its name. Native place the Eastern Seas and Persian Gulf. 



No. 3. Cerithium carinatum. Shell of a rich brown colour, deeply ridged with 

 oblique and transverse furrows ; mouth of a very dark brown ; the spire 

 irregularly bulbous and tuberculous. It is found frequently in the islands 

 of the southern hemisphere. From the Museum of Dr. Lettsom. 



No. 4. Cerithium reticulatum. Shell purple and brown, streaked with brown; 

 mouth of an open form, and expanding sideways. A native of New Cali- 

 fornia. From the Author's Museum. 



REMARKS. 



The genus Cerithium differs in its character so distinctly and accurately from all other 

 shells, that it is surprising how the earlier writers upon Conchology could ever have con- 

 fused it with the Terebra or Aculea. In the length of the spire, indeed, there is a con- 

 siderable resemblance at the first sight; but in the Cerithium it is more irregular, square- 

 shaped, and invested with knobs or protuberances of unequal size. The cheek of the 

 mouth also has generally a great projection beyond the body, and stands in a slanting 

 manner, as if placed on one side; the rostrum or beak is short and recurved. 



