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XXII. Remarks on the Genera Orhicula and Crania of Lamarck, 

 with Descriptions of two Species of each Genus ; and some 

 Observations proving the Patella distorta of Montagu to be a 

 Species of Crania. By Mr. George Brettingham Souerby, 

 F.L.S. 



Bead March 17, J 818. 



The opportunity of addressing the following observations to the 

 Linnean Society of London, has been lately afforded me by a 

 circumstance, very common indeed in its kind, though at the 

 same time I may be allowed to say fortunate, as far as regards 

 the subject of the present communication and its results. 



Among a quantity of ballast lately brought to the parish of 

 Lambeth for mending the roads, were several stones, evidently 

 collected on the sea-coast, and which, in the numerous irregula- 

 rities of their surfaces and the cavities with which they were per- 

 vaded, contained a considerable number of small shells, some of 

 them of singular characters and of uncommon and little known 

 species. I have made several attempts to ascertain what part of 

 the world the ballast was brought from, but all my inquiries have 

 hitherto proved fruitless ; though from some slight circumstances 

 I have reason for supposing that it has been brought from the 

 northern coast of Africa. I could not, however, consider this a 

 sufficient reason for withholding the information I thus have it in 

 my power to communicate, more especially, as the discovery 

 among the shells thus procured, of a species of Lamarck's genus 

 Orhicula, has led to a further discovery of the real character and 



proper 



