32 COCKERELL AND COLLINGE : CHECK-LIST OF SLUGS. 



^ were originally given to the group it represents as a whole, 



but all to separate parts of it. Believing that the rules of 

 nomenclature demand the use of Libania (which seems to 

 be the oldest name), I have sunk Westerlund's name as 

 a synonym. Westerlund recognises nineteen species in the 

 group ; my list contains more, but probably a thorough 

 revision, with ample material, might reduce the species by half. 

 CJilamydephorus. This differs by one letter from the similarly- 

 named genus of mammals, and, from their derivation, the 

 two names should be spelled alike. Apera is occupied in 

 botany, but that is not generally considered to prevent the 

 use of a zoological generic name. On the whole I prefer 

 Mr. Binney's term with the original spelling, but those who 

 use the list can follow whichever course they consider best. 

 It is one of those cases which illustrate the difficulty of 

 strictly applying the laws of nomenclature. 

 Phosphorax and Pltdrophorus. One feels inclined to write 

 Bosh, instead of Bosc, after some of these names ! 

 I merely insert them because they have been published ; 

 the generic and specific characters are purely imaginary. 

 Gray suggested that P. corninus was founded on A. ater, 

 some hardened mucus being taken for a shell. 

 366. Arion ater. It seems open to question whether the species 

 or sub-species called e7iipiricoruni can be separated from 

 the Linnean ater. Dr. Scharff {S/u^s of Ireland^ p. 539) 

 states that he has examined specimens from Norway, and 

 finds less difference between East Irish and Norwegian 

 examples than there is between the West and East Irish." 

 Again, if these forms are to be sub-specifically separated, 

 can we call either of them empiricorum ? Linne {Syst. iVi?/. 

 Ed. X. 1758, p. 652) includes under his ater the Scan- 

 dinavian form, but he also refers to Lister's Limax attr as 

 identical — and this is our English black " empericoriiinr 

 Admitting, however, that ater can be used only for the 

 Scandinavian race, we next come to rufus. A. riifiis, L., 

 is the sub-riifiis of the Fauna Succica, which Pollonera 

 gives as a doubtful synonym of etnpiricoriun, but it is also 

 Lister's L. sub-rjifus Jtiontanus, which is the British form, 

 and there is a reference to Aldrovandi's Limax magna, 

 colore rufo, which is surely also the so-called empiricorum* 



'* Was this not from an external examination only ? — V^. E. C. 

 * I regret that I cannot now examine Aldrovandi's work, to see whether this is so, but there 

 can hardly be a doubt. For an interesting notice of this pioneer in the study of slugs (ob. 1605) 

 see Jardine's Naturalists' Library, vol. xvii. — T. D. A. C. 



