WEST AMERICAN PYKAMIDELLID MOLLUSKS. 203 



ODOSTOMIA (EVALEA) UNALASKENSIS, new species. 

 Plate 2(i, lig. .5. 



Shell elongate-ovate, stout and strong, light yellow. (Nuclear 

 whorls decollated.) Post-nuclear whorls flattened on their outer 

 three-fourth, rounding suddenly to the closely appressed summit, on 

 the posterior fourth. Entire surface of the shell nuirked by lines of 

 growth and numerous equal and equally spaced, well marked spiral 

 striations, of which about 28 occur between the sutures of the penul- 

 timate whorl. Sutures well impressed. Peri})heiy of the last whorl 

 somewhat angulated. Base elongated, rounded, marked like the 

 spire. Aperture ovate, slightly effuse anteriorly, posterior angle 

 acute; outer lip thin; columella short, strongly curved and reflected, 

 reenforced for the greater part by the attenuated base and provided 

 with a strong obHque fold at its insertion; parietal wall covered by 

 a thin callus. 



The unique type, Cat. no. 150464a, was collected by Dr. W. H. 

 Dall, at Captains Harbor, Unalaska, Alaska. It has five and one-half 

 post-nuclear turns and measures: Length 4.8 mm., diameter 2.8 mm. 



ODOSTOMIA (EVALEA) ATOSSA Dall. 

 Plate 26, fig. 8. 

 Odostomia (Evalea) atossa Dall, Proc. U. S. Nat. Mus., vol. 34, p. 253, June, 1908. 



Shell large, ovate, bluish-white. Nuclear whorls small, deeply 

 obliquely immersed in the first of the succeeding turns, above which 

 only the tilted edge of the last volution projects. Post-nuclear 

 whorls inflated, well rounded, feebly contracted at the sutures, very 

 weakly shouldered at the summit, marked by fine, slightly retractive 

 lines of growth, and by 7 well-incised spiral lines on the first, 10 on the 

 second, and 20 on the third. On the last whorl they are very feeble 

 between the sutures, where they are replaced by four slender, spiral 

 threads. Periphery of the last whorl inflated. Base inflated, well 

 rounded, marked by numerous, closely spaced, fine spiral striations. 

 Aperture large, ovate; ])osterior angle acute; outer lip thin; colu- 

 mella moderately strong, strongly curved, decidedly reflected, partly 

 reenforced by the base and provided with a fold at its insertion. 



The type (Cat. no. 110637, U.S.N.M.) and another specimen comes 

 from San Pedro, California. The type has five post-nuclear whorls 

 and measures: Length 6.5 mm., diameter 3.5 mm., and was collected 

 by Mr. H. N. Lowe. 



ODOSTOMIA (EVALEA) OBESA, new species. 



Plate 26, fig. 4. 



Shell large, ovate, yellowish- white. Nuclear whorls very small, 

 very deeply obliquely immersed in the first of the succeeding turns, 

 above which only the tilted edge of the last volution jjrojects. Post- 



