458 TECTURIDiE. 



Fam. TECTURID^. 



Lingual riband long, with two centi-al, and two hooked 

 lateral teeth on each side in an oblique line, the inner 

 often the larger. Head with a short muzzle ; mouth with 

 cartilaginous jaws ; tentacles subulate ; eyes on bulgings 

 at their outer bases. Mantle-margin simple or fringed ; 

 gill forming a single pectinated plume on the side of the 

 back of the neck. Foot large, ovate, with a simple, im- 

 pressed groove. 

 Operculum none. 



Shell depressed, conical, or cap-shaped ; aperture wide^ 

 with a crescentic, muscular impression, interrupted in the 

 region of the head. 



The family of Tecturida, or " False Limpets," is dis- 

 tinguished from that of the PatelUdm, or " True Lim- 

 pets," by the gill being single, and situated in a cavity on 

 the right side of the neck, instead of forming a series of 

 lamellae between the mantle and foot. They are littoral 

 in their habits, feeding on the sea-weed between tide- 

 marks ; their locomotion is very limited, and in their 

 geographical distribution, they are found both in tropical 

 and temperate countries. 



Genus TECTUEA, Audouin and Milne Edwards. 



Mantle-margin fringed ; foot oval, flat. 



Shell patelliform, regular, depressly-conical, surface 

 smooth or with radiating striae ; apex anterior, sub-cen- 

 tral; aperture very wide, muscular impression non-sym- 

 metrical, the anterior part under the right side. 



