262 ACHATINELLA DIMORPHA. 



Sutural band wanting, the other two reduced to lines, 

 either of which is occasionally doubled (pi. 42, fig. 18). 



Only one band, the lower (band iii) remaining (pi. 42, 

 %. 17). 



Only the upper band (ii) remaining (pi. 42, fig. 19). Of 

 this pattern there is only one specimen, all of the others being 

 represented by numerous shells. 



A. contract a Gulick (pi. 47, figs. 19, 20) is in my opinion 

 only a form of the Kaaawa zonata, from which it differs by the 

 shorter contour. Very few specimens were taken. In some 

 of them there are indistinct gray streaks in the ground, which 

 is yellow below, white above the supraperipheral deep chest- 

 nut band. This shell reminds one of a similar form of un- 

 dulata. Possibly there has been some infusion of undulata 

 blood from across the range. No recent collector has to my 

 knowledge found contracta or any of the dimorpha forms in 

 Kaaawa, and they are probably extinct in the places where 

 Mr. Emerson collected fifty or sixty years ago. 



The original descriptions of albescens, zonata and contracta 

 follow. 



Achatinella albescens. " Shell sinistral, sometimes dextral, 

 imperforate, ovate-conic, solid, shining, striated, white or 

 sometimes yellowish ; apex somewhat acute ; spire convexly 

 conical ; suture marginate, well impressed ; whorls 6 ; some- 

 what swollen beneath the suture and slightly flattened in the 

 middle ; columellar fold central, white, strong ; aperture trun- 

 cately auriform, white within ; peristome thickened within, 

 with external margin unreflected, slightly arcuate ; columellar 

 margin dilated, adnate, parietal margin wanting. Length 18, 

 breadth 10%, length of body-whorl 13 mm. Average weight 

 4.6 grains. On the leaves of the pua, ahakea and lama. 

 Waimea, Pupukea, Waialei, Kahuku and Hauula, J. T. G. ! 

 Kaawa J. S. Emerson ! Nearly a third of the specimens from 

 Waimea and Pupukea are dextral, but in Waialei, the metro- 

 polis of the species, they are always sinistral.' (Gulick). 



Achatinella zonata. ' ' Shell sinistral, sometimes dextral, im- 

 perforate, ovate-conic, solid, shining, striated, white or yellow- 

 ish with a brown sutural band and two black bands, one en- 

 tering the aperture ; apex somewhat acute ; spire conical, with 

 outlines slightly convex ; suture marginate, moderately im- 

 pressed; whorls 6, convex; the last regularly rounded; colu- 



