of Great Britain. 103 



rule is applicable, with few exceptions, to all recent cases, where 

 the species described can be properly made out ; but it so happens 

 that it cannot conveniently be brought to bear upon names establish- 

 ed by long use. Any attempt to change these for such as, though 

 really prior, have not been generally adopted, has usually proved a 

 failure, and only tended to increase the confusion it was meant to 

 avoid. Extent of use, therefore, must be taken into account in 

 judging of established names. I am afraid that on this account we 

 shall be obliged to give up some of the names of Montagu which 

 English authors have hitherto retained on the ground of priority. 

 The " Testacea Britannica" was published in 1803, and the " His- 

 toire Naturelle des Mollusques terrestres et fluviatiles de la France" 

 in 1806. There was thus a priority of publication in the En- 

 glish work over that of France ; but notwithstanding this, the 

 authority of Draparnaud has been so thoroughly established, that, 

 though Montagu's book has now been known on the continent of 

 Europe for upwards of twenty years, and his synonyms pointed out 

 in the " Concordance" of Ferussac, yet not one of his names has 

 been adopted in preference to those of Draparnaud by a single con- 

 tinental author. Would it not be better, therefore, for the sake of 

 uniformity of nomenclature, that British authors should give up a 

 point which they cannot carry, and agree in adopting the more ge- 

 nerally received names of Draparnaud ? In conformity with this 

 view, the names of a few species of Helix have been altered in the 

 following list, from those usually given in British catalogues. 



Another circumstance which has greatly increased the number of 

 synonyms is the difficulty of making out the species of some of the 

 older writers, particularly those of Linnaeus, whose descriptions are 

 often very short and unsatisfactory. Much labour has been in vain 

 bestowed in attempting to ascertain many of the land and fresh 

 water shells of this naturalist, and different authors have referred 

 them to so many different species, that there are instances in 

 which two, three, and even four species have been alternately call- 

 ed by the same Linnaean name, according to the peculiar views of 

 the authors who described them. Turbo muscorum of Linnaeus may 

 be taken as an example. The shell called Turbo miiscorum by 

 Montagu, and Tufa muscorum by Fleming, under the belief that it 

 is the Linnaean species, is Pupa umbilicata, Drap. Lamarck, Fe- 

 russac, and others, think differently, and give that name to Pupa 

 marginata, Drap. Draparnaud himself refers it to a third species. 

 Vertigo cylindrica, Fer. which he consequently calls Pupa muscorum. 

 But Dr Turton gives it as his opinion that Pupa edentula, Drap. is 

 the true Turbo muscorum of Linnaeus. Thus to understand what 



