AURICULELLA, OAHU. 87 



dextral], " distinctly longitudinally striate ; whorls 6, flatly 

 convex; suture impressed; apex obtuse. Aperture subauri- 

 f orru, vertical ; lip thickened, duplicate, parietal lamella some- 

 what thin ; coluniellar fold thick, twisted, high ; pale purplish 

 white, base burnt umber, covered with a brown, deciduous 

 epidermis. Length 8 l / 2 , diam. 5 mm." (Pease). 



Oahu: Waianae Mts. (Baldwin, Lyman) ; Palikea (Spald- 

 iug) ; Popouwela (Thaanum). 



Auriculella ambusta PEASE, Journ. de Couchyl., 1868, xvi, 

 p. 345. PFR., Mou. Hel. Viv., viii, p. 211 ANCEY, Bull. Soc. 

 Malac. France, vi, 1899, p. 214. SYKES, Fauna Hawaiiensis, 

 ii, p. 375. Auriculella obliqua ANCEY, Mem. Soc. Zool. 

 France, v, 1892, p. 721.- SYKES, Proc. Malac. Soc. London, 

 iii, p. 275, pi. 13, fig. 17. Fauna Hawaiiensis, ii, p. 377. 



This peculiar species is rather limited in its distribution as 

 it has only been found near the middle of the Waianae Moun- 

 tain range. 



Pease described his shell as imperforate, but a careful ex- 

 amination showed that most of his shells have a minute per- 

 foration, which is sometimes closed by the thickening of the 

 lip, or perhaps always in old shells. The keel-like ridge be- 

 hind the lip, giving it a duplicated appearance, continues on 

 the base. This is unlike A. pulchra, in which the ridge ap- 

 proximates to the basal edge, though prominent behind the 

 outer lip. In A. malleata also, the ridge does not continue to 

 the base, and its crest is rounded, not keeled or angular as 

 in ambusta. The apical whorl is yellow, whitish or bluish- 

 black, spire delft blue (lighter or darker), often brown above 

 the suture, or it may be nearly white or pale yellow, becoming 

 white on the upper part of the last whorl; lower part of the 

 last whorl brown (cinnamon to amber brown), usually more 

 or less covered with a deciduous blackish epidermis, which 

 gives the scorched appearance signalized by the very apt name 

 ambustus. The interior is dark below in many specimens, 

 and there is a short transverse callus at the posterior end of 

 the peristome. A sharp ridge runs outside the outer lip. 

 Length 7.6, oblique diameter 4.5, aperture 4 mm. It turns 

 either way. In one lot from Popouwela there are 9 dextral 

 and 7 sinistral individuals. 



