PARTULINA, LANAI. 89 



shell. The animals of the two species are somewhat similar, 

 but sufficiently different to warrant the separation ' (Bald- 

 win). 



It is a local race of the highest peak of Mt. Lanaihale. 

 The color-patterns of the type lot are shown in pi. 21, figs. 5, 

 6, 7. It is uniform orange-rufous with the tip of the apex 

 pale, aperture pink; the same with a white subsutural band; 

 or in addition to this there may be a white band or bands mid- 

 way between the sutures on the spire, gradually deepening 

 on the penult, whorl, to the ordinary ground-color. 



In a series of 29 shells, collected by Mr. D. Thaanum, pi. 21, 

 figs. 8 to 12, 5 -are sinistral. the rest dextral. The sinistral 

 shells have the color-patterns described above, the last whorl 

 being uniform orange-rufous. Seven of the dextral shells are 

 exactly similar in pattern to the sinistral, and they differ from 

 P. semicarinata only by the deeper shade of color. Ten adult 

 dextral shells are pale-yellowish flesh-tinted with several or 

 numerous orange-rufous bands, varying in intensity among 

 the specimens. 



Embryo. A dextral specimen of the typical orange-rufous 

 color with white sutural band on the spire only, contained 

 three embryos, two having a white sutural band, a white 

 band a short distance below the suture and white columellar 

 area, the other being multilineate with brown above and 

 below. A dextral banded snail (pi. 21, fig. 10) contained 3 

 embryos, two 3-banded with some accessory lines, the other 

 having numerous weak bands. In both examples the embryos 

 are dextral. 



It seems likely that the ancestral stock of semicarinata was 

 banded, and typical hayseldeni is a more evolved form in 

 which the banding has been replaced on the lower whorls or 

 throughout by the dark color of the bands, while typical pale 

 semicarinata has lost its bands entirely or on the later whorls. 

 The whole series is so closely interrelated that I do not think 

 it divisible into two species. I retain the name hayseldeni in 

 a varietal sense because it is already in the literature, rather 

 than from any real distinction, as I believe the intergradation 

 with semicarinata is practically -complete. 



