AURICULELLA, LANAI AND MAUI. 107 



Species of Lanai. 

 25. A. LANAIENSIS Cooke, n. sp. PL 19, figs. 12 to 16. 



The shell is perforate, sinistral, ovately conic, light cinna- 

 mon with base slightly lighter, somewhat thin, not diapha- 

 nous, hardly glossy, under a lens rather finely striate with 

 lines of growth. Spire nearly conic, apex rather obtuse. Su- 

 ture lightly impressed, simple. Whorls 6, slightly convex, the 

 last rotund, subsaccate at the base. Aperture broadly oval, 

 slightly diagonal, very slightly oblique. Parietal lamella very 

 slightly developed. Columella simple, scarcely dentate. Lip 

 erect, very slightly thickened, the outer margin curved, the 

 columellar margin reflexed. Umbilicus rather small, subcircu- 

 lar. Length 5.8, diam. 3.0 mm. 



Lanai (Thaanum). 



Of thirty-four specimens examined, all are sinistral. Some 

 of the largest shells measure nearly 7 mm. in length, while 

 smaller adult specimens are scarcely 5 mm. long. Unfortu- 

 nately, my specimens were preserved in formalin so that the 

 exact texture cannot be noted. The chief characteristic of 

 this species is the very minute parietal lamella, and a ten- 

 dency of most of the shells to a light-colored base. This is 

 emphasized, in some of the shells, by a dark band at the 

 periphery. This species is most closely related to A. flavida. 

 The latter is usually dextral, and the parietal lamella is more 

 strongly developed; the shell is also more diaphanous. 



Probably the specimens reported from Lanai as A. brunnea 

 belong to this species. 



Species of Maui. 



The three Mauian species are very closely related, and their 

 discrimination is sometimes difficult. They are also closely 

 allied to the Molokaian A. brunnea. All are quite solid, 

 opaque shells. 



a. Shell very broad at the base ; umbilicus conspicuously open. 



expansa, no. 28. 

 a 1 . Shell normal in form; umbilicus moderate or small. 



b. Shell very solid, with a conspicuous tubercle at upper 

 angle of aperture. crassula, no. 27. 



