296 FAUNA HAWAIIENSIS 



Fam. ACHATINELLIDAE. 



The various species of this family form probably one of the most puzzling groups 

 of land-shells known : numerous ' species ' have been described, founded almost entirely 

 on shell colouration or banding, and this, bearing in mind such protean forms as Tachea 

 nemoralis or Polytnita picia, is a course which often leads to endless trouble. At present, 

 such genera as Achatinella s. s. and Achatinellastriim are in utter confusion, and any 

 attempt at a list of species simply reflects the general view of the writer and cannot be 

 regarded as authoritative. 



Of recent years some species have been described, based on shell-colouration com- 

 bined with that of the mantle, but it should be remembered that some malacological 

 characteristics are frequently as liable to variation as are conchological ones. The 

 severance of species by consideration of habitat is, again, not a necessarily certain 

 guide, since one species of mollusc may range widely, while at different points of its 

 range, local variations may occur. 



The history of the Achatinellidae in literature commences with Dixon's description 

 of Turbo apexftdva ; subsequently stray species were described by various authors, but 

 no serious attempts were made at their study until about 1850-60, when Newcomb and 

 Pfeiffer added greatly to our knowledge. To Mr Gulick, in 1858, we owe large addi- 

 tions to the catalogue — so far as names go — but his views of species were somewhat 

 too narrow, and he described many trifling variations as species, mainly on the ground 

 of geographical range. Later, Pease did useful work and gave a catalogue of the family. 

 Dr Hartman, in 1888, listed the known forms in a similar way. Of recent years Mr 

 Baldwin has done the chief work on the group, and his very valuable catalogue has been 

 of great assistance. 



Numerous genera and sections have been described, almost all on purely concho- 

 logical grounds, and so variable are the forms that linking species are easily found. 

 Still they prove useful in the arrangement of species and therefore have been admitted 

 in this work. 



A list of them arranged in chronological order may be of use. 

 1828. Achatinella Swainson, O. J. Sci. Lit. and Arts, p. 81. 



1847 

 1854 

 1854 

 1854 

 1854 

 1854 

 1854 



Leptachatina Gould, P. Boston Soc. 11. p. 201. 

 Partulina Pfeiffer, Malak. Blatt. i. p. 114. 

 Newcoftibia Pfeiffer, /. c. p. 1 1 7. 

 Bulimella Pfeiffer, /. c. p. 11 9. 

 Laniinella Pfeiffer, t. c. p. 126. 

 Ackalinellastriiin Pfeiffer, t. c. p. 133. 

 Labiclla Pfeiffer, /. c. p. 142. 



