BARTSCH: NEW ENGLAND PYRAMIDELLIDAE. 97 
Key to the Subgenera of Odostomia. 
A. Whorls nodulose between the sutures Chrysallida. 
AA. Whorls not nodulose between the sutures. 
a Spiral markings consisting of fine lirations. 
Axial ribs present on the posterior half of the whorls between the sutures 
Evalina. 
aa. Spiral markings consisting of well developed cords, axial sculpture 
reduced to mere raised lines, confined to the grooves between the 
cords. 
b. Shell umbilicated lolaea. 
bb. Shell not umbilicated Menestho. 
aaa. Spiral markings absent or if present consisting of extremely fine 
microscopic striations only. 
Columellar fold present Odostomia. 
Columellar fold absent Liostomia. 
Chrysallida Carpenter. 
Chrysallida Carpenter, Cat. Mazatlan shells, p. 416, 1856,= Noemia De 
Folin, 1870,= Noemiamea De Folin, 1885 (not Noemia Pascal, 1857). 
Shell ornamented between the sutnres by axial ribs and spiral cords, 
the junctions of which form nodules; base spirally grooved; grooves 
crossed by numerous slender axial lirations. 
Type, Chemnitzia communis C. B. Adams. 
Key to the Species of Chrysallida. 
All four spiral keels nodulous between the sutures. 
Shell large, adult about 3.8 mm. or more seminuda. 
Shell small, adult about 2.5 mm. or more willisi. 
Only three spiral keels nodulous, the anterior one smooth . . hushiana. 
Odostomia (Chrysallida) seminuda C. B. Adams. 
PI. 13, figs. 45, 48. 
Odostomia semimida C. B. Adams, Boston journ. nat. hist., vol. 2, p. 280, 
pi. 4, fig. 13, 1839. 
Shell very elongate-ovate, milk white. Nuclear whorls at least two, 
smooth, depressed helicoid, a little more than half obliquely immersed 
in the first of the succeeding turns. Post-nuclear whorls well rounded, 
somewhat shouldered at the summit, ornamented between the sutures 
by nodular axial ribs of which 18 occur upon the 2d; 22 upon the 3d; 
