Three New Species of Amastra from Oahu 



Bv C. Montague Cooke, Jr. 



During the last few months Mr. Irwin Spalding has found a 

 number of interesting forms of Amastra. Three of these are en- 

 tirely distinct from anj- of the species already described. Some of 

 the other forms do not agree with any description but may be re- 

 ferred, as varieties, to some of the spceies already described. 

 It seems strange that all of the three species described here are 

 found within five miles of Honolulu. 



\ 



Amastra irwiniana, n. sp. 



FiK- 3- 

 The shell is minutely (though distinctly) perforate, dextral, 

 globosely conical, with slightly concave outlines, thin, distinctly 

 irregularly and closely striate with lines of growth, not glossy, 

 the upper whorls and the base of the last whorl light brown with 

 a slightly yellowish tinge, the upper portion of the last whorl of 

 a dark chestnut. vSpire slightly concavely conic, apex acute. 

 Suture simple, well impressed. Whorls 6X. the embryonic slight- 

 ly swollen, the fourth and fifth slightly flatter, the last convex, 

 tumid, with an almost obsolete angle at the i)eriphery, tapering 

 towards the base. Aperture rather large, l)luisli within, in the 

 form of a slightly oblique sector of a circle, very slightly oblique. 

 Columella straight ; columellar fold almost median, rather large, 



Oc. p. B. p. B. M.. Vol. III.,No. 2— a. L^'SJ ^'^^ 



