TKITONIID^. 101 



Fam. TRITONIID^. 



Teeth on lingual membrane In seven rows (3.1.3.), cen- 

 tral generally toothed ; lateral in three series, converging, 

 the inner often broad, the two outer subulate, versatile. 

 Mantle enclosed, siphon straight. Foot small. 



Operculum ovate, annular, nucleus subapical. 



Shell with varices on the whorls ; aperture with a 

 straight canal in front. 



The Tritoniida have been hitherto united with the 3Iu- 

 ricidee, but the teeth of the latter are in three rows only, 

 while, in this family, they assimilate with the dentition of 

 Velutinidce and Naticidee, where they are arranged in 

 seven series. 



G-enus TRITONIUM, Link. 



Shell oblong; spire prominent, whorls with a few remote 

 and non-continuous varices ; columella rough or smooth ; 

 canal recurved, short or long ; outer lip internally crenated 

 or denticulated. 



Syn. Triton, Montf., not Laur. Buccinum, Browne^ 

 not Linn. Charonia, Gistel. 



Ex. T. nodulum, 3Iartim, pi. 11, fig. 1. Operculum, 

 T. pileare, Linnaeus, fig. 1, a, \, h. Shell, T. Tritonis, 

 Linnaus, fig. 1, c. 



The Tritons are principally equatorial in their geogra- 

 phical distribution, and belong more especially to the 

 Asiatic fauna. Those with the canal very much produced 

 are obtained from deep water ; the cancellated forms are 

 from sand, in deep water ; and those covered with an epi- 

 dermis are chiefly from sandy mud, in from six to thirt 

 fathoms. 



luJ i L J B R A ?8 



