180 MALACOZOA. GASTEROPODA. CYCLOBRANCHIATA. 



GENUS 1. PATELLA. LIMPET. 



Animal elliptical or roundish, convex, covered by a 

 Univalve conical shell ; head with two conical tentacula, 

 bearing the eyes at their base internally ; mouth fleshy, 

 transverse, with a short proboscis, and containing an 

 extremely elongated, linear, flattened organ, covered on 

 one side with tufts of small spines symmetrically disposed, 

 and directed backwards into the intestine ; stomach 

 membranous ; intestine long, convoluted ; foot very large, 

 elliptical or roundish, marginate ; branchiae apparently 

 formed of the lower thickened margin of the mantle. 



Shell conical, with the apex nearer the anterior end ; 

 the aperture extremely large, elliptical, ovate, or round- 

 ish. 



The species adhere to rocks, stones, fuci, and other 

 objects. 



1. Patella vulgdta. Common Limpet. 



Shell conical, with the outline of the mouth obovate or ro- 

 tundato-obovate ; the apex nearer the anterior or smaller end ; 

 the surface radiated with about eighteen ribs alternating with 

 striae, and crossed by concentric striae ; the colour dusky-green 

 with rays of yellowish-grey, the interior greyish- white, beyond 

 the attachment of the mantle rayed with dusky and yellow, 

 appearing through a transparent iridescent layer. Length an 

 inch-and-a-half or more, height ten-twelfths or more. 



Varies greatly in form, some individuals being roundish, 

 others ovate, some very high, others low ; in tbe number and 

 size of the ribs, the degree in which they render the margin 

 undulated; and in the colours, which may be yellow, grey, 

 red, olivaceous or dusky, plain or in bands. " Quiconque 

 n'aurait qu'un exemplaire de cette coquille, pourrait se trouver 

 fort embarrasse pour le rapporter a son espece, tant celle-ci est 

 variable ; aussi les auteurs different-ils beaucoup dans les 

 descriptions et les figures qu'ils en donnent." 



The animal may be described as flat and with an oval out- 

 line beneath, convex above. If examined from beneath, it 

 will be seen to present a roundish expanded, flat, foot, of 

 which the surface is smooth, and of an olivaceous colour, mar- 

 gined with a thick yellow rim, and attached to the shell by in- 



