of the Piedmontese Coast. 177 



for the latter species, and I therefore give the names chiefly 

 on his authority. I have adopted the arrangement of the 

 ' British Mollusca/ as preferable to that of Philippi, who used 

 Lamarck^s system. The accompanying plate contains figures, 

 from Mr. James de Carle Sowerby's well-known and accurate 

 pencil, of my new species, and of Bulla ovulata, which was 

 indifferently figured by Brocchi. I have not thought it neces- 

 sary to particularize the localities, except in a few instances of 

 rare or peculiar species. 



Any attempt to tabulate, with precision, the per-centage or 

 proportion of Mediterranean species, in comparison with those 

 of Great Britain, would be unsatisfactory, as it must necessarily 

 fluctuate with the continual discovery of new species. The 

 general (although confessedly imperfect) result at which I have 

 arrived from my own investigation and reference to other lists 

 is, that out of about 500 species of British marine Testacea, 

 one half are identical with those of the Mediterranean, and that 

 we possess consequently about 250 species which have not yet 

 been described or indicated as Mediterranean. The species of 

 Mediterranean Testacea probably nuiyber 850, out of which 

 about 600 have not yet been described or noticed as British. 



The works which I have consulted in the preparation of this 

 memoir, and especially with regard to the question of geogra- 

 phical distribution, are, — Brocchi's ' Conchiologia Fossile Sub- 

 apennina,^ Philippics 'Fauna Molluscorura utriusque SiciliBe,^ 

 Forbes and Hanley's 'British Mollusca,^ Smithes 'Mediterranean,' 

 Searles Wood's ' Crag Mollusca ' in the Palseontographical So- 

 ciety's publications, Lyell's 'Principles of Geology' (ninth 

 edition), Maury's ' Physical Geography of the Sea,' Hooker and 

 Thompson's ' Flora Indica,' Eisso's ' Fauna of Southern Europe,' 

 Payraudeau's ' Mollusca of Corsica,' D'Orbigny's Contribu- 

 tion to Barker- Webb and Berthelot's ' Natural History of the 

 Canaries,' Professor Edward Forbes's Reports to the British 

 Association, and Mr. MacAndrew's Pamphlet on the Geogra- 

 phical Distribution of the Testaceous Mollusca in the North 

 Atlantic and neighbouring seas (1854), besides many other 

 scattered contributions to natural history. 



Acephala Lamellihranchiata, or Bivalves. 



Septaria MediterraneOy Lam. Nice. 

 Teredina personata, Lam. Nice ! 

 Teredo navalis, in ships' bottoms. Nice. 

 Saxicava Arctica, Phil. ^ Brit. Moll. 

 Venerupis Irus, Ph. ^ B. M. 



Corbula nucleus. Ph. ^ B. M. — C. rosea (Brown, 1827), B. M. 

 (C. Mediterranea, Costa, 1829, Ph.). Besides the localities indicated 

 Ann. ^ Mag. N. Hist. Ser. 2. Vol. xvii. 12 



