PABTULINA DUBIA, OAHU. 115 



straight light yellow and 'brown streaks on the post-em- 

 bryonic whorls. The smallest adult seen is 16 mm. long. 



Probably all of Newcomb's shells, to which the above notes 

 apply, were from the Waianae range, where it has been found 

 in Makaha valley (on the southern side) by Mr. Spalding, 

 and perhaps elsewhere by other collectors. PI. 26, fig. 8, is a 

 Waianae range shell. 



In the main range P. dubia, has an extended distribution, 

 from Waimano to Waialua or Kawailoa, but only in a few 

 places, so that it is regarded as a rather rare shell. Very fine 

 series are in the collections of Messrs. Spalding, Emerson and 

 Wilder. As a general rule, main range shells have a more 

 thickened lip than those of Waianae, and the apex is often 

 perceptibly blunter, whorls a trifle more convex ; so far as I 

 know, no sinistral shells have been found ; but I am not satis- 

 fied that these small differences hold in all specimens. * 



In Waiawa (pi. 26, figs. 9, 9a, 9&, coll. by Spalding in the 

 eastern ravines) the shell is streaked and mottled, with 'boldly 

 zigzag-striped last embryonic whorl ; or similar with a whitish 

 peripheral band and several lines. Others are chestnut with 

 pale streaks, a white peripheral band and several spiral light 

 lines, the white zigzags of the embryo very much reduced 

 (pi. 26, fig. 9 &), or white may predominate, the chestnut 

 being reduced to bands narrower than 'the white, one speci- 

 men. In a few the later whorls are whitish with brown stains 

 (pi. 26, fig. 9). 



An extraordinary series was collected by Mr. Spalding in 

 Waimano. Most of the colony is of the usual streaked and 

 mottled form, but in a few the color is very deep, rich brown 

 (between liver-brown or carob-brown and black, of Ridg- 

 way's Color Standards). This may be uniform or varied 

 with light buff bands. The embryonic whorls are brown with 

 light bands and lines, and on the last embryonic whorl there 

 is a trace of the light stripes of the typical form. The figures, 

 pi. 26, figs. 10, 10a, are from two specimens of Mr. Spalding 's 

 no. 2181. This color-form is one of the rarest Oahuan tre3 

 snails. A suspicion has been entertained that it might be a 

 hybrid between diibia and- a rare black form of Ach. turgida ; 



