GENUS XXXn. PATELLA. 137 



vulgata ; ia others it is near the margin, as Pectuiiculus, &c. ; 

 in some few the tip is lengthened somewhat spirally, as mili- 

 taris and iingarica ; several have a small aperture at the tip 

 (the Perforatce of Linnaeus), as grtvca, &c. ; in n)any the 

 margin is angular or wrinkled : these arc the Dentatcs of Lin- 

 naeus : as P. octoradiata, &c. : many have the margin cre- 

 nate, with small wrinkles more or less obscure, as ungarica, 

 &c. &c. : a few have the margin quite smooth, as P. coeridea. 



Some of the first division have a horizontal partition extend- 

 ing about half way, as P. forniccia ; others have a lateral 

 partition extending from the tip to the margin nearly, as 

 P. chinensis ; others have only an irregular process project- 

 ing inside the tip, as P. eqiiestris. All these Linnaeus calls 

 Labiatce. 



One or two shells that appear to be bivalves have been 

 placed in this genus by some authors, and consequently ought 

 to be removed : the Patella Unguis of Linnaeus and Gmelin is 

 the Mytilus Rostrum of Dr. Shaw and Turton, and the P. ano- 

 mala of Gmelin and Turton is nearly allied to, if it is not strictly 

 an Anomia: according to Lamarck, P. sinica is also a bivalve. 



The animal of the Patella is somewhat like that of the Ha- 

 liotis ; it has a cylindrical head, two tapering nearly cylindri- 

 cal horns, with the eyes on the external side of the base : this 

 animal is scarcely capable of extending any part beyond the 

 shell more than the tips of the horns. 



Linnaeus has described 36 species, Gmelin has added 201, 

 and Dr. Turton 3. Total, 340. 



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