AURICULELLA, OAHU. 89 



few elevated wrinkles descending forwardly like many Lim- 

 naeas. Aperture subauriform, angulate above, spreading and 

 receding below, oblique, furnished with a quite thin or mod- 

 erate parietal lamella and with a not prominent, slightly ob- 

 tuse, sometimes indistinctly duplicate columellar lamella. Lip 

 thickened, expanded at the base, exteriorly margined, with the 

 margins joined by a callus bearing a tubercle or swelling at 

 the juncture, flattened further down, and slightly carried for- 

 ward in the middle. Length 9, diam. 4.25; alt. ap. (oblique) 

 4.5 mm." (Ancey). 



Oahu: Summit of Mt. Kaala, in the Waianae Mts. (Thwing, 

 Cooke). 



Auriculella malleata ANCEY, Proc. Malac. Soc. London, vi, 

 1904, p. 120, pi. 7, fig. 12. 



"Related to A. obliqua Ancey found on Oahu, but much 

 more slender, malleated, and tinged with brown on the earlier 

 whorls" (Anc.). 



This is a very distinct species and is not abundant in any 

 locality. The forwardly-descending malleation is very dis- 

 tinct in some of the specimens. The small umbilicus appears 

 acutely ovate from below. The shape is narrower, more ob- 

 long than in the allied Waianaean species A. ambusta. So 

 far as known it is always white, very solid, with the outlines 

 of the spire slightly convex and the summit perceptibly nip- 

 ple-like. There is a low swelling or rounded ridge behind the 

 outer lip, but not a sharp ridge such as malleata, obliqua and 

 pulckra have. Usual size 8.8 mm. long, 4 mm. in oblique 

 diameter. A form of ambusta is sometimes slightly malleate. 



Group of A. perpusilla. 



The shell is small, perforate, thin, more or less translucent, 

 composed of few (less than 6) convex whorls; lip expanded, 

 but very slightly thickened. Columella straight or having 

 an obtuse median fold. 



The young are imperf orate, obliquely angled at the periph- 

 ery ; columella with a rather strong, transverse, thin fold. 



Three species, in the main range of Oahu. The strong con- 

 vexity of the whorls of the spire distinguishes these species 

 from the preceding and following groups. 



