WINCKWOETH .* BRITISH LITTORINID^. 97 



Genus MELARHAPHE, Menke, 1828. Type : Paludina glahrata = 

 Turbo neritoides, L. 



3. Neritoides (L.), 1758. Linne's species is the Mediterranean 

 shell, and if a name is required to distinguish our race, which only 

 difiers slightly from it, we can use Montagu's name jpeircea. 



Genus NERITOIDES, Brown, 1827. Type : Nerita littoralis, L. 

 Dautzenberg and Fischer, in Journ. de Conchyl., Ixii, 1915, 

 pp. 87-128, have given a full account of the species ohtusata and 

 littoralis and their variation. Littorina cestuarii, Jeffreys, seems 

 a good species, and Dautzenberg, in correspondence 1920, regards 

 it as distinct. 



4. Obtusata (L.), 1758. The type specimen is figured by Hanley 

 in Ipsa Linnaei Conchy lia. It is the same as Litorina arctica, 

 Moller, and the American race is L. palliata, Say. Occurrence in 

 Britain doubtful. 



5. tEstuarii (Jeffreys), 1869. 



6. Littoralis (L.), 1758. The northern subspecies is v. compacta, 

 Jeffreys. The typical subspecies includes v. pachychila, D. & F., 

 and V. retusa, Lamarck ; the former is the thick heavy shell common 

 on both sides of the English Channel, the latter is the same as 

 neritiformis of Brown. 



My thanks are due to Mr. Iredale and Mr. Tomlin for help with 

 literature. 



*:}.* Note added after reading by permission of the Publication 

 Committee. 



Although I have followed M. Dautzenberg above in regarding 

 Turbo saxatilis, Olivi, as conspecific with T. rudis, Maton, I think it 

 better to retain the latter name for our British forms, until Olivi's 

 species has been examined anatomically. The very close resemblance 

 between the isolated Venetian colony and some forms of our species 

 may be only convergence of shell form, when we recall how close 

 some forms of rudis and littorea are in shell characters, so that they 

 are not easily distinguished without examining the soft parts. 



Another point raised in discussion was that as the distinctions 

 between the genera were mainly methods of reproduction, they were 

 cecological, and should have no place in a classification based on 

 morphology. The two closest groups are Littorina s.s. and Neritoides, 

 and to my mind the distinction between a mollusc with a free 

 veliger stage and one that does not pass through this stage still 

 seems of generic importance ; while in the other groups the genera 

 could be separated on anatomical and conchological distinctions. 

 Those who do not see with me in this may regard the names as of 

 subgeneric rank. . 



This seems a good opportunity for killing the name Bacalia, 

 Gray, 1840, a nomen nudum which becomes valid in 1854 when 

 H & A. Adams introduced it in synonymy in Genera, i, 312. I choose 

 as type littorea; Linne ; it thus becomes an absolute synonym of 

 Littorina, Ferussac. 



