72 AURICULELLA. 



genus. Gulick, in 1873, seems to have followed him; but 

 Pfeiffer did riot use Auriculella in a generic sense until 1877. 



Pease recognized 11 species in 1868; Pfeiffer, 18 in 1877; 

 Ancey, 24 (Bui. Soc. Malac. France, VI, 1889, pp. 211-235), 

 and Sykes (in Fauna Hawaiiensis, II, Moll., pp. 375-379), 20 

 species. 



Distribution. Of the 30 species of this genus, recognized 

 in this monograph, 19 are from Oahu, 5 from Molokai, 3 from 

 Maui and one each from Lanai and Hawaii. Kauai is with- 

 out a described species at present, though there are three lots 

 in the collection of the Bishop Museum from this island. Two 

 of these lots, each containing a single specimen, are undoubt- 

 edly A. auricula. They are probably the result of a more or 

 less recent introduction. The third lot consist of two or three 

 adult specimens and several immature. All of these closely 

 approach A. diaphana, and, until more material has been col- 

 lected, are referred to this species. Except for the two species 

 mentioned above, no one species has been found on more than 

 a single island. The species which have been reported from 

 more than one island by earlier authors have not been care- 

 fully determined. 



Specific characters. Most of the species are rimate when 

 adult, but in all the axis is imperf orate when immature. 

 Nearly all of the thicker species have numerous color forms, 

 but most of the thin species are unicolorous. The color-pat- 

 terns (which are made up of white, yellow and different 

 shades of brown) usually take the form of revolving bands 

 and lines. In only a few cases are the shells longitudinally 

 striped. When this is so the patterns are not distinct, and 

 are made up of brown and brownish-corneous. 



The peristome is always more or less thickened in adult spe- 

 cimens. In the thinner species it is usually a slightly darker 

 shade than the shell, but in the thicker multicolored species 

 it may be either white or very dark. In adult Auriculellas 

 from Oahu the columella is furnished with one or two folds. 

 Most of the species from the islands east of Oahu have a sim- 

 ple unarmed columella. The columella of all immature spe- 

 cimens is furnished with one or two folds. 



