ACHATINELLA LEUCORRAPHE. 303 



face is eroded, it becomes dark flesh color), changing to cinna- 

 mon buff or some ochraceous tint on the last two embryonic 

 whorls. Later w r horls white, encircled with black lines or lines 

 and bands, most numerous on the base ; the lines above the 

 periphery often weak and yellowish. Sutural margin usually 

 white, sometimes with a dark line. Peristome pinkish lilac. 



Length 19, diam. 13.3 mm. ; whorls 6. 



Length 16.7, diam. 11.9 mm. ; whorls 6y. 



Division ridges between gulches of Kipapa and Waikaka- 

 laua, Waikakalaua and Kalaikoa, and Kalaikoa and Kaukine- 

 hua, above the 1,500 ft. contour, extending up each ridge to 

 within a mile of the main ridge ; abundant on mokihana, ieie, 

 lehua and alani (Irwin Spalding). 



By its clean-cut bands on a white ground and dark apical 

 spiral this form resembles A. vittata simulans of the Nuuanu- 

 Kalihi ridge, to the point of identity. An expert might dis- 

 tinguish between good lots of each; nobody could rightly 

 separate a mixed lot. Yet the very identity of patterns and 

 their geographic discontinuity makes us suspect it highly un- 

 likely that they belong to the same species, for no Achatinella 

 is known to hold a pattern unchanged over so great a dis- 

 tance. It appears that we have to do with two species which 

 have evolved along parallel lines; a smaller western stock in 

 which some colonies retain the ancestral streaked pattern, 

 and a larger eastern, in which the streaked pattern is 

 now rare and rather unlike that of the western species. It is 

 the final stages of each which are so remarkably alike. The 

 nearest colonies of simulans and irwini are separated by fully 

 one-fourth the length of Oahu, where neither is found, al- 

 though some similar races of other species occur, such as A. 

 turgida simulacrum. 



Mr. Spalding has noted that from Waikakalaua four-fifths 

 of the shells are dextral, and in Kaukinehua one-half are 

 dextral. The white ground and dark apex are constant, but 

 there is ample variation in the number and width of the bands. 

 The size varies from about 16 to 19 mm. The banded form 

 from the upper part of the Kaukinehua ridge, figs. 11 to 11&, 

 may be taken as typical of irwini (from 10A nearly to the 



