1917.] NATURAL SCIENCES OF PHILADELPHIA. 325 



Length 2.2, cliam. 0.85 mm. ; 5| whorls in all. 



This small, smooth species appears to belong to the section 

 Brack !/stomia. 

 Odostomia iNesiodostomiai prima n. sp. Fig. 27. 



Mokapu Point, Oahu. Type No. 117622, A. N. S. P., collected 

 by W. A. and E. L. Bryan. Paratypes in Bryan collection. 



The shell is cylindric-fusiform, strong, glossy, white, with a broad 

 gray margin below the suture and a broad tawny zone in the middle 

 of the last whorl, its upper edge showing as a band above the suture 

 on two or three whorls preceding. Sculpture of indistinct spiral 

 impressed lines, rather widelj' spaced, and a few irregular axial 

 lines. The nuclear whorl projects somewhat nipple-like, its tip 

 turned in. Subsequent whorls are nearly flat, parted by a narrowly 

 but deeply cut suture. The aperture is narrowly piriform. The 

 outer lip is thin, and arches slightly forward. The inner margin 

 is, covered with a heavy callous, which spreads well forward. It is 

 straight except near the base, where it passes into the narrow, deeply 

 concave columella. Internally there is a spiral fold, which does not 

 emerge to the aperture, and is visible only on breaking the shell. 



Length 7.4, diam. 2.2, length of aperture 3.2 mm.; 7 whorls. 



This species may be considered the type of the subgenus Nesio- 

 dostomia, characterized by the straightened inner lip, covered with a 

 heavy, spreading callous, the columellar fold deeply immersed. The 

 aperture is shaped much as in Siihularia. 

 Odostomia (Nesiodostomia) secunda n- sp. Fig. 28. 



Mokapu Point, Oahu. Type No. 117620, A. N. S. P., collected 

 by ]Mrs. A. F. Letson. Paratypes in Bryan collection. 



The shell resembles 0. prima in form. It is chamois colored, 

 imperfectly transparent, having a wide gray sutural margin. The 

 surface is glossy, and shows some impressed axial striae. The last 

 whorl descends shortly to the aperture. 



Length 4.2, diam. 1.3, length of aperture 1.6 mm.; 5 post -nuclear 

 whorls. 



While this is evidently adult, by the descent of the suture just 

 preceding the aperture, it is much smaller in all its parts than 0. 

 prima, and quite unlike young shells of that species of the same 

 length. 

 Odostomia (Nesiodostomia) tertia n. sp. Fig. 29. 



Paumalu, Oahu. Type No. 117621, A. N. S. P., collected by 

 W. A. and E. L. Bryan. 



The shell is aculeate, the upper half of the spire attenuated, lateral 



