PARTULINA, LANAI. 85 



all sinistral. (c) White, with a faint yellow or brown stain 

 within the lip- callus, 7 shells, one of them sinistral. Resem- 

 bles lactea except in the paler aperture. Fig. 11. (d) Cream 

 colored, darker towards the base, to ochraceous with darker 

 streaks, bandless, the peripheral angle usually conspicuous, 

 but wanting in 7 shells; 16 specimens, six of them sinistral, 

 pi. 22, fig. 12. Of 4 embryos taken from a banded shell, 

 fig. 10, three are banded as in pi. 21, fig. 16, the fourth, 

 fig. 17, being ochraceous with a white band below the periph- 

 ery, which is more distinctly carinate than in the others. 

 Of 5 embryos from a pure white shell, fig. 11, three are dis- 

 tinctly ochraceous, one having a white band below the 

 periphery ; the others being white. 



It appears that some colonies are exclusively sinistral, 

 others wholly dextral, the same color-patterns running 

 through both. Other colonies contain both sinistral and dex- 

 tral forms, and a variety of color-patterns, which are unlike 

 in the proportions of sinistral and dextral individuals. In 

 mixed colonies, left-handed coil and banding seem to be 

 dominant, right-handedness and plain color recessive. The 

 diversity of young taken from one parent indicates hybridity 

 between the color-forms, but data are wanting to show 

 whether sinistral and dextral forms hybridize. 



The three-banded type, with bands placed as in the Mauian 

 P. nattii f is probably the most fundamental (or nearest to the 

 ancestral) pattern. 



A. fulva (' Newcomb ' Pfr.), pi. 22, figs. 13, 14, is not dis- 

 tinguishable from the tawny-ochraceous form occurring in 

 colonies of variabilis. In sonie specimens the periphery is 

 acute in front of the aperture, but in others more accelerated 

 it is rounded. The original description follows : Shell sub- 

 perforate, turrite-conic, solid, striatulate, and under a lens 

 very delicately decussate, glossy, buff-tawny; spire sub- 

 concavely conic, the apex white, acute, suture thread-mar- 

 gined; whorls l / 2 , the upper fiat, following ones convex, the 

 last a little over one-third the total length, swollen below the 

 suture, base sac-like. Aperture oblique, subtetragonal-auri- 

 form, columellar fold superior, nodiform, orange colored; 



