50 PEOCBEDINGS OF THE MALACOLOGICAL SOCIETY. 



Discus, Fitzinger^ : " Genus Helicoideorum, ex typis Helicis 

 rotundatfB, ruderatge, crystallinae." 



Strange bedfellows, some of these, and hardly good instances of 

 the selection of a type. 



Again^ one and the same species is not infrequently named, as 

 " typus " to two genera. Thus, Helix cellaria appears for both 

 Oxychilus and Polita ; H. fruticum for both Eulota and Fruticicola ; 

 H. pisana for both Euparypha and Xerophila ; Area nooz for both 

 Byssoarca and Navicula. Or we have two types for genera that are 

 synonymous, as Helix nemoralis for Cepcea, and H. hortensis for 

 Tachea. 



The author's object was obviously to cite types for the variolis 

 minor genera while leaving it to those who used his index to settle 

 whether a given genus and consequently its type be valid or not.^ As 

 he himself says : — 



" Nihil de novo condendo systemate hie loci dicam, nil de clavi 

 Malacozoorum conficienda, aut synonymia specierum elaboranda. 

 Quae . . . maxime necessaria, aliis relinquere cogimur." 

 (Proemium, p. iv.) 



J. E. Gray, in his " List of the genera of recent MoUusca, their 

 synonyma and types " (Proc. Zool. Soc, 1847, pt. xv, November, 

 p]3. 129-219), after insisting " in the importance of attending to the 

 law of priority . . . now almost universally allowed " although 

 " quite prepared for hearing several conchologists complain of the 

 changes which the observance of this just law will force them to 

 make", gives the following outline of his procedure as regards 

 types : " The method I have followed is to observe the first name 

 given to the genus and the type on which it was founded, and then to 

 accumulate the synonyma around the genus. Where a succeeding 

 author has referred to a different species as the type of the genus, 

 I have given the name a new line, as at some future period that type 

 may be proved really to belong to a difierent genus. . . In respect to 

 . . . works which only give the genera, and simply mention one or 

 two examples as the types of their genus, the species they give as 

 types are here cited ; but in works like Linnaeus's " Systema 

 Naturae ", and Lamarck's " Histoire ", which give the species of 

 Mollusca, it is not so easy to determine which species the author 

 intended for the type of his genus. In these cases I have chosen 

 either the best known species, or, if the author has given figures, the 

 specimen which he has figured. . . In the Linnsean genera, in which 

 there is room for doubt ... I have considered the name as restricted 

 to the type which the earliest author after Linnaeus has quoted for 



1 Cf. Kennard & Woodward, Proc. Malac. Soc, xiv, J920, p. 85. 



^ In this connexion it should be borne in mind that after Vol. ii, p. 232, 

 " Peripatus," Herrmannsen's selected types may have been anticipated by 

 Gray (Nov., 1847). 



