CERTTHIID^E. 255 



four keels or rows of tubercles ou the last whorl, I 

 should have been inclined to consider our shell identical 

 with it. 



Family XXV. CERITHI'ID^E, (Cerithiadw) 



Fleming. 



Body spiral, elongated : mantle fringed at its outer edges, 

 and forming in front a very short semitubular fold, which is 

 not protruded beyond the notch in the shell : head snout-like 

 and contractile ; there is no proboscis : tentacles awl-shaped, 

 separate at the base, and connected by a sinuous veil or mem- 

 brane : eyes placed on bulgings outside the base of the ten- 

 tacles : foot lanceolate: gill-plume single, composed of triangular 

 plates : jaws or cheek-plates triangular : odontophore very short 

 and straight, spinous ; teeth 3.1.3. Sexes distinct. 



Shell pyramidal, nearly always tuberculated, sometimes 

 furnished with varices or persistent edges of the mouth, never 

 umbilicate : spire tapering to a fine point : whorls numerous : 

 suture slight : mouth small ; groove at the base short and re- 

 curved : operculum horny, nearly circular, and spiral, with few 

 whorls ; nucleus not quite central, but on the inner side of 

 the mouth. 



An extremely prolific and widely diffused family, 

 having perhaps few genera, although these abound in 

 species both recent and fossil. The latter are almost 

 countless. Deshayes, a long time ago, enumerated 

 between 400 and 500 fossil species of Cerithium ; and 

 they have since multiplied beyond all reasonable bounds. 

 Quousque ? Their sculpture is very elegant and diver- 

 sified ; Lamarck recommended it to architects as a pat- 

 tern for the ornamentation of columns. With respect 

 to the animal, I would advise conchologists to study 

 the careful observations of my friend Mr. Berkeley, on 

 the anatomy of C. telescopium, in the 5th volume of the 

 ' Zoological Journal/ 



