ACHATINELLA CASTA. 235 



is usually purple ; in only a very few cases is the columella 

 white. Of this group 48 per cent, came from sub-ridge XIV ; 

 44 per cent, were found on lehua, 12 per cent, on Straussia, 

 and 43 per cent, on guava. 



"The fifth group is made up of color- varieties E-T. The 

 shell is white, variously striped ; the apex is white ; columella 

 is usually purple. About 60 per cent, were found on lehua, 

 15 per cent, on straussia, and 19 per cent, on guava. This 

 group is distributed over nearly the whole range of the species ; 

 only five specimens were found below sub-ridge XIV. 



"The sixth group is made up of the color- varieties V-Y. 

 The shells are variously colored from a rich mahogany brown 

 to a pinkish purple. The apex is usually banded; in some 

 cases it is white. The columella is usually purple. All ex- 

 cept two specimens came from sub-ridge XV-XVII; 75 per 

 cent, were found upon lehua. This group comes nearest, in 

 color, to A. bellula Smith, but differs in form and size from 

 that species [but was later considered to be bellula by Dr. 

 Cooke]. 



"The seventh group is made up of the color-variety Z. 

 This color-variety agrees with several of the other color-varie- 

 ties in the markings of the lower whorls, but differs from them 

 in the very dark banded apex. Of this group 96 per cent, 

 were found on sub-ridges I and II ; 70 per cent, were found 



on guava, and 23 per cent, on lehua There are seven 



of the color-varieties of which over 95 per cent, came from 

 two or three consecutive ridges. ... In this species it can be 

 seen that isolation plays a greater part than environment. ' 



20. A. CASTA Newcomb. PI. 41, figs. 12 to 16 ; pi. 49, figs. 1 to 16. 



' ' Shell conically elongate, solid, polished, shining, dextral or 

 sinistral ; whorls 6, rounded, margined above ; aperture sub- 

 ovate, rather small ; lip simple, thickened within ; columella 

 short, with a strong plaited brownish tooth. Color white or 

 yellow, with extremely variable transverse bands of black, 

 brown, pink or white, variously arranged. Length 13 twen- 

 tieths, width 6!/2 twentieths of an inch. Ewa; its northern 

 limit is the valley below Mouna Rua, and a half dozen ravines 

 south, in the district of Ewa' : (Newcomb). 



