124 Original Desaiptions of Achatinella. 



199. Achatinella hawaiiensis Baldwin. 



A. hawaiiensii Bald. P. Ac. Philad., 1S95, p. 225, pi. x, figs. 24-26. 



Shell sinistral, minutely perforated, very thin, acutely conical, 

 apex acute; surface rather lustreless, covered with fine lines of 

 growth, and under a lens showing extremely close and delicate 

 decussating spiral lines; nuclear whorls faintly decussated. Color 

 very variable, plain brown or dingy white, sometimes irregularly 

 striped or mottled with brown or white, the base uniformly brown, 

 but sometimes with undulating markings of brown and white; the 

 only constant characters being a brown, sometimes interrupted, 

 line at the periphery, bordered below with a broader white line. 

 Whorls 6, slightly convex, the last inflated. Suture lightly im- 

 pressed. Aperture oblique, oval, brown, the peripheral brown 

 and white bands distinctly marked within. Peristome acute, not 

 thickened within, external margin straight, basal expanded, the 

 expanded portion being very thin and fragile, the columellar mar- 

 gin reflected over the minute perforations; color white on both 

 face and the reverse. Columella white, very slightly developed, 

 plain and smooth. Length 18, diam. 10 1-2 mm. 



Animal when extended in motion longer than the shell. Mantle 

 almost white, margin of a darker shade. Foot above and below 

 dingy white, superior portion sometimes flecked with gray. Ten- 

 tacles of darker shade. 



This species also belongs to the group of A. physa Newc, but 

 is readily distinguished by its smaller size, smoother surface, deli- 

 cate lip, and arrangement of colors. The habitats are also widely 

 separated, and the animals differ. — Bald. 



Hab. Hamakua. — Bald. 



200. Achatinella horneri Baldwin. 



A. horneri Bald. P. Ac. Philad., 1895, p. 224, pi. x, fig. 20-22. 



Shell sinistral, minutely perforated, thin, globose with a short 

 acutely conical spire, apex acute; surface shining, striated with 

 fine incremental lines, and under a lens exhibiting very close and 

 delicate and decussating spiral strite; embryonic whorls faintly 

 cross-lined. Color dull white, encircled at the periphery with a 

 faint brown zone, which is continued on suture, also with a very 

 small patch of the same color around the umbilicus. Whorls 6, 

 the upper five slightly convex, the last very much inflated, forming 

 the greater part of the shell; suture distinctly impressed. Aper- 

 ture oblique, subrotund, very large, white within, distinctly 

 showing the external peripheral band, peristome margined with 

 light brown, rather thin, very slightly thickened within, expanded, 

 basal and columellar margins narrowly reflected, extremities 



