PARTULINA, OAHU; EBURNELLA. 67 



(c) Length 26.9, diam. 13.1, length aperture 12.1 mm. 



Oahu: Man-oa road at its junction with the upper road, 

 back of Rocky Hill, cotypes (a) no. 108181 A. N. S. P.; (&) 

 no. Ill coll. Irwin Spalding; and (c) no. 33581 B. P. Bishop 

 Mus. Also found on Rocky Hill about ^4 niile from the type 

 locality. 



Partulina montagui PILSBRY, Nautilus, xxvii, p. 40, August 

 1st, 1913. 



This species differs strikingly from all others by its sculp- 

 ture and small apical whorls. It seems to be nearest to P. 

 dwightii of Molokai. No specimens yet found show any trace 

 of color. The periphery is angular in the young, the angle 

 persisting as far as the last whorl in some individuals. 



It was first found by Dr. C. Montague Cooke. The shells 

 occur in the humus near the surface, along the roadside, and 

 are very rare, apparently lying in " pockets " which have 

 been filled and covered by the wash down the slope. Probably 

 the forest disappeared from where the shells are found not 

 much more than a hundred years ago. 



Section Eburnella Pease. 



Elurnella PEASE, P. Z. S., 1869, p. 647. GULICK, P. Z. S., 

 1873, p. 91, as section of Partulina] A. variabilis selected as 

 an example. 



Very smooth, glossy shells, uniform white, yellow or brown, 

 or variously banded, not striped longitudinally; outer lip 

 simple or scarcely expanded; columellar fold strong. Type 

 P. variabilis (Newc.). 



The typical group consists of Lanaian species in which the 

 peripheral keel persists throughout the young stages, and 

 often upon the first half of the last whorl. In the allied 

 groups of Molokai and Maui the keel is lost much earlier ; the 

 later stages of youth and the mature stage being round at 

 the periphery. The group is not strongly individualized, 

 some species, as P. mutabilis, showing transition to the pattern 

 of Perdicella, others approaching Partulinae of the striped 

 group of Maui. 



Eburnella was originally a heterogeneous group comprising 



