SHELLS WITHOUT A REGULAR SPIRE. 59 



Ge«ws31.— HALIOTIS. 



Animal a Limax ; shell ear-shaped ; univalve and dilated, 

 vv^ith a longitudinal row of orifices opening on the surface; 

 spire lateral, and nearly concealed. 



The animals composing- the shells of the genus Haliotis, inhabit the 

 sea only. They adhere closely to rocks, and can only be removed by 

 suddenly snatching them from their hold. In some places the animal 

 is esteemed good eating. One species, the HaUotis tuberculata, is very 

 common in Guernsey, and sold in the market as food. 



HaUotis tuberculata The Tubercular Haliotis. 



Plate IX. fig. 31. Dull reddish brown on the outside, 

 sometimes clouded or mottled with a deeper shade : longi- 

 tudinally striated, and transversely wrinkled, with a few 

 raised tubercles; inside perlaceous, reflecting the most beau- 

 tiful shades of pinis:, blue, green, and yellow; aperture open 

 the whole length of the shell, outer-lip irregular. From 

 three to four inches long. Inhabits the sea at Guernsey. 



It is asserted, that as a new hole is added by the animal to the shell, 

 it carefully closes up the next open one to the spire ; by which means 

 the number of orifices is, in general, the same in all shells of one 

 species. 



DIVISION SECOND.— SHELLS WITHOUT A REGULAR SPIRE. 



Genus 32 PATELLA. 



Animal a Limax ; shell univalve, subconic, shaped like a 

 bason ; without a spire. 



Linnteus divides this genus into five families : *furnished with an in- 

 ternal lip ; shell entire ; **with the margin angular or irregularly 

 toothed; ***\nth a pointed recurved tip or crov^^l ; ****vei'y entire, 

 and not pointed at the tip or vertex ; ****«with the crown perforated. 



Patella vulgata — The Common Patella. Plate IX. 

 fig. 32. Subject to great external variety ; ribbed from the 

 vertex to the margin in some specimens, and with divergent 

 •striae; others striated merely, without ribs; of a dark brown 

 or olive green on the outside, and the inside blue, shining 

 with deep purple radiations; and presenting a great variety 



