182 ACHATINELLA, SECT. ACHATINELLASTRUM. 



and (5) A. papyracea. Westward we find the connected series 

 (6) A. livida curia dimorpha, with a distinct satellite 

 species, (7) A. casia. The "Waianae species are as yet but 

 little known, and apparently are distinct. 



Much remains to be done in the definition of the critical points 

 where one polymorphic population gives place to another, 

 especially in the western half of the Main Range. It is quite 

 likely that further collections and study will modify our 

 present specific boundaries, or perhaps abolish some of them. 



I have not constructed a key to the forms of this group 

 for the reason that most species of Achatinellastrum vary 

 widely in color. Such small differences in size and shape as 

 there may be in the average between allied species, are usually 

 covered by individual variation. I fear that any key I could 

 make would surely mislead anyone who attempted to name 

 single specimens by it. The expert will naturally turn to the 

 group or "series" to which his unnamed shell belongs. Those 

 without special knowledge of Achatinella will doubtless most 

 easily get from the plates a clue to what they seek. 



Series of Achatinellastrum. 



Series of A. vulpina. Eastern end of the Main range, west 

 to Manana. Mainly rather large and moderately strong 

 shells, conspicuously colored, green, yellow or chestnut, gen- 

 erally streaked or banded, rarely white. Species no. 14 to 18. 



Series of A. casta. Tantalus to Helemano. Smaller shells, 

 whitish, yellow or chestnut, usually with bands. Species no. 

 19 to 21. 



Series of A. papyracea. Middle of Main range. Rather 

 capacious, ovate, thin shells, the embryonic whorls not marked 

 with an ocher band. Species no. 22. 



Waianae Range species, intermediate between the papy- 

 racea and livida series. Species no. 28 to 30. 



Series of A. livida. Western half of the Main Range. 

 Rather small, stout, ovate or short shells, dull green, yellow 

 or white, often with a few bands, or sometimes streaked; 

 embryo often with an ocher band. Species no. 23 to 27. 



