96 HOLOSPIRA. 



increasing, forming a high cone, the later whorls slightly 

 decreasing, a little convex, the suture moderately impressed; 

 last whorl with swollen rounded base, somewhat ascending in 

 front, very shortly produced forward. Aperture vertical, 

 subcircular; peristome a little thickened throughout, nar- 

 rowly expanded, white, the upper margin transverse, outer 

 angle distinct, the margins elsewhere arcuate, (v. Mart.} 



Length 16, diam. penult, whorl 4, greatest diam. 5, length 

 aperture 3% mm. 



Length 14%, diam. penult, whorl 3, greatest diam. 3%, 

 length aperture 2% mm. 



Length 12, diam. penult, whorl 3, greatest diam. 3%, length 

 aperture 2%. 



S.-W. Mexico: Omilteme, State of Guerrero (H. H. Smith). 



Holospira fusca v. MART., Biologia Centrali Americana, 

 Moll., p. 281, pi. 16, f. 19-24 (December, 1897). Holospira 

 umbilicata v. Mart., SOWERBY & FULTON on label. 



Chiefly remarkable for the brown color and comparatively 

 large internal column, which is at least usually open below. 

 This column is pale brown with the usual whitish lines in 

 its substance, and within several of the later whorls it is per- 

 ceptibly swollen just below the middle, as in Coclocentrum. 

 In a shell with 16% whorls, measuring, length 12, diam. 3.4 

 mm., the column is 1.3 mm. wide, being over one-third the 

 diameter of the shell. The first and second whorls are wider 

 than the third. 



Only large specimens have as many as 19 whorls, those of 

 12 to 13 mm. length having only 16% to 17. The shells be- 

 fore me (figs. 8, 9, 10, part of the original lot) are brown, 

 and in a slight degree translucent, the internal axis showing 

 faintly through in one specimen. Figs. 11-14 are from von 

 Martens' original illustrations. 



Subgenus METASTOMA Strebel, 1880. 



STREBEL, Beitrag, etc., iv, p. 80, for M. roemeri Pfr. 



Internal column smooth and cylindrical, of moderate size; 

 without internal lamellae. Last whorl sinuous, it's latter por- 

 tion turning sinistral. Aperture longitudinally oval, ob- 



