286 AMASTRA, MAUI. 



The typical form of A. soror may be considered that illus- 

 trated by Newcomb, whose figure is copied in our pi. 48, fig. 

 5. It is a variable species but whether the individual colonies 

 are homogeneous or not we do not know. The spire is brown, 

 darkest above, very little contracted near the summit; last 

 whorl (or last two whorls) opaque yellow or buff, glossy, re- 

 taining fragments of a very thin olive or brown cuticle. 

 First half-whorl of the embryo smooth, next whorl finely cos- 

 tellate, the riblets 'Curved ; next whorl with much finer riblets, 

 as usual ; a keel is visible just above the suture. Following 

 Whorls have a weak sculpture of low but nearly regular 

 wrinkles along lines of growth. A delicate keel is visible on 

 some of the whorls, just above the suture, and sometimes it 

 extends as far as the penult, whorl. The aperture is white 

 within, lip acute, slightly or heavily thickened within. Colu- 

 mellar lamella moderately strong, axis closed in specimens 

 examined. 



Length 13.8, diam. 7.1, aperture 6 mm. ; 6% whorls. 



The specimens described and figs. 1, 2 are no. 1566, Boston 

 Soc. N. H., from Lahaina, Gulick coll. 



There is also a more slender form in coll. A. N. S. P. (pi. 

 48, figs. 3, 4). The spire is more contracted near the apex. 

 The embryonic whorls are more finely striate and without 

 distinct keel or angle above the suture. Following whorls 

 have irregular wrinkles of growth, and are rather glossy. 

 On the longest shell seen, a carina is visible above the suture. 

 The >aperture is very oblique, white, a little thickened within 

 the outer lip. The columella is very short, dilated above, 

 nearly closing the perforation. It bears a quite small fold 

 which is larger within. The color is reddish-brown at the 

 apex, gradually fading downwards, the last whorl being very 

 pale-brown or white, with traces of a very thin brown cu- 

 ticle. 



Length 14, diam. 6.1, aperture 5.1 mm. ; 7 whorls. 



Length 13, diam. 6.1, aperture 5.1 mm. ; 6% whorls. 



The exact locality of the type specimens as well as of this 

 more slender form is unknown. This slender form may be 

 referable to the following variety. 



