20 New Species of Amastra. 



lighter colored shading to a broad white patch behind the peris- 

 tome. Spire conic, with an acute apex and almost straight out- 

 lines. Embryonic whorls somewhat extended, flatly convex, the 

 first smooth and polished, the second minutel}' closely striate. 

 The following whorls are nearly flat, obliquely sculptured with 

 rather coarse irregular growth- wrinkles. The last whorl is short, 

 strongly carinate (the carina appearing above the suture of the 

 last two whorls), with a flattened base, somewhat contracted about 

 the umbilicus. The carina is slightly granulose, flattened below 

 and its lower margin being bordered by a shallow sulcus. The 

 aperture is small, very oblique, distinctly contracted above, nearly 

 quadrate, in outline, the outer margin modified by the carina form- 

 ing an obtuse angle; above the carina the margin is somewhat 

 flattened, below regularly slightly arcuate, forming an angle with 

 the base of the columella and furnished wath a thin delicate lip-rib. 

 The columella is narrowly triangular, its inner margin slightly 

 oblique, the outer margin thin, semierect. Columellar fold large, 

 nearly basal in position, subtransverse, ending abruptly at the outer 

 margin of the columella. The umbilicus is nearly circular, with a 

 rather acute, slighth^ contracted margin, wider within. 



lyCngth 10.9, diam. 7.4, apert. 4.6 mm.; 6 whls. (Holotype) 

 " 8.7, diam. 7.3, apert. 4.6 " 5^^2 " 



Hawaii: Pleistocene at Huehue about 1,800 feet elevation 

 (A. Gouveia, L. A. Thurston); Puwaawaa (A. Gouveia). 



Holotype and cotypes No. 41,974, paratypes No. 41,975, 

 Bishop Museum. 



This remarkable species is provisionally placed in Ainastrclla 

 though it and A. fragosa might appropriately form the nucleus of 

 a new section or subgenus. Except for the presence of an umbili- 

 cus .4. />a^^^?</a appears to be a diminuative A. kauaiensis. In 

 some of the specimens there is a slight concavity to the spire. 

 Immature specimens have a much stronger peripheral keel than 

 adults. Some of the specimens appear to have died only recently as 

 the color is antique brown with a broad whitish basal patch about 

 the umbilicus. The embryonic shells are biconic, angled at the 

 periphery and openly perforate. The columellar fold is minute, 

 thread-like, oblique and submedian in position. The specimen 

 from which the second series of measurements was taken, though 

 consideral)l\- shorter and having half a whorl less than the type, is 

 an adult shell with a well-defined lip-rib slightly more developed 

 than that of the type. [238] 



