364 JOURNAL OF CONCHOLOGY, VOL. lO, NO. 12, OCTOBER, I903. 



Planorbis crista (Linn.). — This appears in the loth edition of the 

 "Systema" as Nautilus crista and was changed in the 12th edition by 

 Linnd to Turbo nautileus. The loth edition being now agreed upon 

 as the starting point the specific name of crista must stand. 



Planorbis [ffelix] planorbis (Linn.). — A reference to the figures 

 cited by Linn£eus shows that, as Hanley points out, two species P. 

 umbilicatus and P. carinatus were included; consequently Miiller's 

 names must be accepted. 



Planorbis \Helix\ complanatus (Linn.) is as Hanley points out most 

 applicable to the P. nitidus Miiller as the "convexa, subtus plana" 

 clearly shows. Both Miiller and Jeffreys overlooked the fact that 

 Linne's Helix planorbis contained Miiller's P. umbilicatus and rashly 

 identified his Helix complanatus with the latter's P. timbilicatus. 



Planorbis nitidiis Miill. — This may or may not be the same as 

 Linnd's Helix complanatus but it is identical with the Helix lineatus of 

 Walker, as proved by the type specimens in the Copenhagen Museum. 



Bulinus Adanson, 1757, is not only pre-Linnean, but was founded 

 to include molluscs quite distinct from our British form and belonging 

 moreover to the Planorbidse. Hence Fleming's Aplexa in its amended 

 form of Aplecta must be accepted. 



Hydrobia Hartmann, being preoccupied according to our notions by 

 Hydrobius Leach, for Coleoptera, D'Orbigny's name Paludestrina 

 should be taken: those, however, who follow the American school 

 will probably adhere to Hydrobia. Paludestrina has already been 

 adopted in the Society's "Marine List." 



Hydrobia similis Drap. having, as pointed out by Frauenfeld,^ a 

 concentric operculum, whereas the form that has usually passed under 

 the name has a spiral one, the two must be considered distinct. 

 Frauenfeld, therefore,- proposed for the latter the name of Amnicola 

 confusa. The selection of the genus, however, does not seem to 

 accord, Amnicola being rather an American form, hence I follow Mr. 

 Smith and place it in Paludestrina under Frauenfeld's specific name. 



Pseudamnicola anatina is here included on Dr. Boettger's identifica- 

 tion of specimens from Oulton that lacked both animal and operculum. 



Bithynia. — This generic name Mr. C. Davies Sherborn points out 

 to me was first established in Abel's "Narrative of a Journey into the 

 Interior of China," 1818, p. 362, when it appears in its correct spelling, 

 unspoilt by Gray whose mangling of the word lead Jeffreys into a 

 false etymology.^ 



Viviparus having precedence over Paludina^ must stand but the 



1 Verhandl. zool.-hot. Gesellsch, Wien, vol. 12, p. 1151 ; vol. 13, p. 1029. 



2 Op. cit., vol. 13, p. 1029. 



3 Cf. paper by Rev. G. A. Frank Knight,/. Conch., vol. 9, p. 273. 



4 Cf. Smith, /. Conch., vol. 6, p. 333. 



