176 Mr. J. G. Jeffreys on the Marine Testacea 



Grayana, Limneus involutus, and others, have in our own coun- 

 try, and how local and apparently capricious appears to be the 

 distribution of many species. 



The speculation as to the successive and recent creation of 

 species appears to me very questionable, and more abstruse than 

 that of geographical distribution ; because we do not know the 

 extent of modification to which species originally created have 

 been subject, nor whether all existing species, or the remains of 

 former species, have been either discovered or destroyed. Hum- 

 boldt has characterized this subject as one of the mysteries 

 which natural science cannot reach. 



Although considerable pains have of late years been taken to 

 reconcile the labours of British and Continental naturalists, 

 much yet remains to be done. The former want of intercourse 

 between naturalists of our own and other countries, arising 

 from continual warfare, national jealousies, and the difficulties 

 of travelling and communication, has unfortunately caused 

 great confusion in the nomenclature of science ; and no pains 

 ought to be spared in removing it as much as possible, giving 

 due credit to authors of every nation according to the priority 

 of publication. To give some idea of the multiplicity of names 

 which have been given by different authors to the same species 

 of Testacea, 1 may mention that for our common cockle (the 

 Cardium edule of Linnseus) and its varieties, no less than sixteen, 

 and for our oyster fourteen different names have been assigned 

 by British, French, Italian, and German conchologists ; and for 

 another shell [Bullaa scabra of Miiller), six generic and seven 

 specific names have been given by British, Danish, Norwegian, 

 Italian, and American writers ! 



The opportunities which have thus occurred to me of a care- 

 ful examination and comparison of an extensive series of Medi- 

 terranean species, and especially those of the more difficult 

 genera (such as Rissoa and Odostomia), have led me to form 

 what I believe to be more just conclusions with respect to the 

 same species in Great Britain ; and the result will be shown in 

 the subjoined list. That list contains all the species which I 

 found on the Piedmontese coast, as well as some which I ob- 

 served in M. Verany's collection from Nice and Genoa. I have 

 added a few remarks as to some of these, and the descriptions 

 of ten new species. The names of recorded species are those 

 of Philippi and the authors of the ' British Mollusca,' except in 

 a very few cases where it appeared to me necessary to adopt or 

 notice those given by earlier discoverers. Those species which 

 were not found by myself, but were communicated by M. Verany, 

 or noticed by me in his collection, are distinguished by italics. 

 I had no means at the time of making out the synonymy 



