420 patellidtE. 



PATELLA, LiNN^us. 



Shell ovate, or nearly round, conical, with a subcentral 

 anteal apex, surface smooth, or with radiating striae or 

 ribs ; interior with a crescentic muscular impression, inter- 

 rupted in the region of the animal's head. 



Animal with two subulate tentacles, bearing eyes on 

 the outer sides of their swollen bases ; mantle-margin 

 fringed ; branchial plume forming a fixed cordon of minute 

 close-set plates, placed between the mantle and base of 

 foot, and ranging nearly round the body ; foot a large, 

 ovate, or round disk, with plain sides. Buccal mass with 

 cartilaginous jaws ; lingual ribband very long, armed with 

 transverse ranges of teeth, of which six in each series 

 belong to the rachis, flanked on each side by three ac- 

 cessorials. 



The Limpets, properly so called, few as the species are 

 upon our shores, though none of our Gasteropods are so 

 prolific individually, may be grouped under two sections, 

 to which the names Patella and Patina were respectively 

 applied by Dr. Leach, who appears to have regarded 

 them as distinct genera, probably more from love of 

 excessive analysis of species than from knowledge of their 

 true differences, since, so far as we are aware, the dis- 

 tinguishing characters have not been noted. In the rock 

 Limpets (Patei,la, as P. vulgata, and P. athletica), the 

 branchial cordon extends very nearly round the body, 

 being unsymmetrically interrupted on one side near the 

 neck, and the mouth is emarginated below ; in the 

 seaweed Limpets (Patina, as pellucida), on the other 

 hand, the branchial cordon is interrupted for a consider- 



