364 PROCEEDINGS OF THE NATIONAL MUSEUM. 



ODOSTOMIA (ODOSTOMIA) HILGENDORFI Clessin. 



Plate XXIV, %. 5. 



Odostomitt hllyendorji Clessin, Mart. Chem. Condi. Cab., 2d ed., Pyramid., 1900, 

 p. 119, pi. xxvin, fi». 5. 



Shell broadly elongate-conic, veiy regularl}^ tapering, .'^iil)tui-rited, 

 milk-white. Nuclear whorls two and one-half, small, helicoid, well 

 rounded, moderately elevated, about one-third immersed in the fii-st of 

 the later whorls, having their axis almost at a right angle to them. 

 Fost-nuclear whorls rather high between the sutures, flattened, sub- 

 tabulately shouldered at the summits and decidedly angulated at the 

 periphery, marked bv lines of growth and extremely tine, microscopic, 

 clo.sely placed, wavy, spiral striations. The shouldered summits of 

 succeeding Avhorls fall quite a little anterior to the angulated periph- 

 ery, giving the whorls a decidedlv constricted appearance at the 

 sutures, which appears decidedly channeled. Peripher}^ of the last 

 whorl decidedh' angulated. Base slightly rounded, marked like the 

 spaces between the sutures. Aperture suboval, po.sterior angle obtuse 

 (outer lip fractured), thick; columella strong, curved, provided with 

 a prominent lamellar plate at its insertion; parietal wall covered 1)}" a 

 moderately thick callus. 



The specimen described is Clessin's type and was collected by Hil- 

 gendorf at Hakodate. It has seven post-nuclear whorls and measures: 

 long. T) nun.; diam. 2.4 mm. There is a possil)ility that this may be 

 one of A. Adams's species of Odostomia. The description of Odostor 

 mia xuhanguhda A. Adams reads not unlike this, but al)senceof meas- 

 urements, etc., make it impossible to be certain. Clessin's figures, as 

 usual, fail to delineate the characters of this form. No trace of the 

 peripheral angulations is shown. 



ODOSTOMIA (ODOSTOMIA) LIMPIDA, new species. 



Plate XXVI, iijr. 7. 



Shell slender, elongate-conic, semitranslucent, shining. Nuclear 

 whorls moderately large, almost completely oblique!}' immersed in the 

 tirst of the succeeding whorls; the peripheral edge only of the last 

 volution is visible above this. Post-nuclear whorls rather high 

 between the sutures, slightly rounded (almost flattened), faintly 

 shouldered at the summit, apparently without axial or spiral sculi)- 

 ture. The whorls are feebly angulated at the periphery, and the sum- 

 mits of succeeding turns fall a little anterior to it, which renders the 

 sutures well impressed. Base of the last wiiorl large, rounded, very 

 narrowly um])ilicated. Aperture large, .sultovate, somewhat produced 

 at the junction of the outei- lip and columella. })()sterior angle acute, 

 outer li|) (iiiii: columella slender, decidedly curved and somewhat 



