270 SIPHONARIID.E. 



Fain. SIPHON ARIIDiE. 



Lingual membrane broad, ratber long ; teeth numerous, 

 equal, in slightly- arched, cross lines ; the central tooth nar- 

 row, elongated, with a small rhombic apex; the lateral 

 teeth larger, diverging, gradually diminishing in size towards 

 the outer side of the series, and furnished with a rather 

 oblique curved tip. Head with a large frontal disk, bi-lobed 

 in front, and formed by the expanded tentacles ; eyes sessile 

 on the outer side of the disk. Respiratory orifice covered by 

 a large fleshy lobe of the mantle. 



Operculum none. 



Shell conical, patelliform, with an internal groove on the 

 right side. 



The character of the lingual dentition in this family, 

 which is very similar to that of E/lobium, and the closed 

 respiratory cavity, protected, as in Chilina and Ancylus, by 

 a fleshy lobe of the mantle, seem to indicate this to be the 

 true position of these animals. 



Genus SIPHONARIA, Blainville. 



Shell limpet- like, orbicular, depressly conical ; apex sub- 

 central, oblique, recurved posteriorly ; aperture wide, margin 

 irregular, crenulated ; muscular impression crescentic ; a 

 siphonal groove on the right side, which is extended in a 

 projection beyond the margin. 



Syn. Liria, Gray. Trimusculus, Schmidt. 



Ex. S. picta, D'Orbiyny, pi. 84, fig. 10, 10, a. Shell, 

 S. sipho, Sowerby, fig. 10, b. 



The species of Sij)honarta are marine, being found ad- 



