96 GEOLOGICAL MEMOIRS. 



Gmelin and Lamarck, for the accurate statement of localities, so 

 that the results obtained and recorded in this memoir concerning 

 the geographical extension of the Mediterranean mollusca are 

 necessarily very incomplete. Notwithstanding this, the publication 

 of them will not, I hope, be thought superfluous ; since a know- 

 ledge of the geographical extension of the mollusca is a matter far 

 more important in reference to Geology than a similar knowledge 

 concerning other classes of animals. 



The fossil remains of mollusca must always be the main ob- 

 jects of investigation in researches concerning the age and history 

 of the crust of our earth ; and on their authority must be deter- 

 mined a multitude of important geological questions. It can hardly 

 require proof that an acquaintance with the geographical extension 

 of these animals at present, affords the only safe foundation for 

 such researches concerning fossils ; and I turn now at once to the 

 results obtained by my own labours. 



1. Comparison of the Fauna of Greenland with that of South Italy. 



The " Fauna Groenlandiae " of Otto Fabricius was long the only 

 work on Greenland I could avail myself of ; and up to the publica- 

 tion of my second volume of the " Enumeratio," I should have been 

 obliged to limit myself to this as the only authority. Fabricius gives 

 (from No. 381 to 427.) only forty-six species of shell-bearing mol- 

 lusca, to which must be added two Cephalopoda, a Doris, an .ZEoris, 

 and the Clio borealis (the Ascidia, which I have also omitted in the 

 " Enumeratio," not being counted). Very lately, however, a com- 

 plete catalogue of the Greenland mollusca has appeared from M. 

 H. P. C. Moller (Index Molluscorum Groenlandiaeu Hafniae, 1842). 

 Of the mollusca there enumerated, the following species are met 

 with in the Mediterranean : 



Octopus granulatus. Tellina fragilis L. 



Area minuta. Saxicava arctica L. 



Mytilus edulis L. Teredo navalis. 



2. Comparison of the Fauna of Great Britain with that of South 



Italy. 



Of no country is the fauna generally, and that of the mollusca 

 in particular, better known than of Great Britain, although the 

 hitherto standard works of Donovan, Montague, &c, are almost un- 

 known on the Continent ; and neither Lamarck nor Deshayes have 

 generally used them. A very good outline of the English mollusc- 

 fauna will be found in Fleming's " History of British Animals," 

 Edin. 1828 ; and, although this author has often, and as if inten- 

 tionally, made use of generic names in a sense quite different from 

 that of the founder of the genus, I have found it easy, with the 

 help of Montague, to identify the names. 



The list enumerated by Fleming, compared with that which I 

 have obtained from South Italy, stands as follows, according to the 



