PARTULINA, SECTION PERDICELLA. 15 



Sections of Partulina. 

 a. Columellar fold prominent, heavily calloused. 



b. Spiral sculpture distinct, at least at the early whorls; 

 shell not brilliantly glossy. 



Section Partulina s. str., species 8-35. 



ft 1 . Spiral sculpture weak or obsolete; shell smooth and 

 glossy, light colored, uniform or banded. 



Section Eburnella Pse., species 36-47. 

 a 1 . Columellar fold wanting or weak, not calloused. 



6. Spire slenderly conic; rather capacious forms; outer lip 

 narrowly expanded. 



Section Baldwinia Ancey, species 48-53. 

 b l . Shell small, oblong or oblong-conic; outer lip not ex- 

 panded. 



Section Perdicella Pse., species 1-7. 



Section PERDICELLA Pease. 



Perdicella PEASE, P. Z. S., London, 1869, p. 648. SYKES, 

 Fauna Hawaiiensis, Mollusca, p. 329, type A. helena Newc. 



Small Partulince having protractive stripes on the last embry- 

 onic whorl, later whorls striped or with a peripheral band; 

 sculpture Partulinoid; columella nearly straight, or if developed 

 the columella fold is moderate, convex, scarcely or not truncate; 

 outer lip thin, not expanded. Type P. helena Nc. 



Perdicella differs from Partulina by the unexpanded outer lip, 

 the weakness of the columella fold and the small size of the 

 shell. In coloration and sculpture it is altogether Partulinoid. 

 This affinity was recognized by Gulick, who in his classification 

 of 1873 ranked Perdicella as a section of Partulina. Such species 

 as fulgurans, theodorei and winniei are directly intermediate be- 

 tween Perdicella and Partulina. Perdicella is not closely related 

 to Baldwinia, although in both the columellar fold has degener- 

 ated. It is a branch from the tessellata or marmorata series of 

 PartuiinaB. 



Key to Species of Perdicella. 



a. Molokai. Shell sinistral, usually with a light or dark band. 



P. helena j no. 1. 



