284 SPIROSTEMMA. 



narrow and unicuspid, and the laterals have expanded meso- 

 cones and ectocones subterminal on the basal-plates, and (3) 

 the jaw is delicate and plaited. They differ from Urocoptis 

 in (1) the very much smaller size of the teeth and their vastly 

 greater number, and (2) the cusps of the teeth, which present 

 the extraordinary feature of being serrate at the cutting 

 edges. 



Both genera are Jamaican. The rank and affinities of 

 neither have hitherto been recognized. They may be distin- 

 guished thus : 



SPIROSTEMMA. Pillar-shaped, widely truncate at the sum- 

 mit; dull red or brown in color. Last whorl with a strong 

 keel denning a concave basal area. Axis slender, cork-screw 

 twisted in the last whorl or more, where it adheres to the 

 lateral walls of the shell ; and it is never thickened or truncate 

 below. Aperture rounded above, the peristome continuous. 

 Terrestrial. 



ANOMA. Fusiform, or at least rapidly tapering above to a 

 narrow truncation; surface glossy, often variegated with 

 bands or stripes; basal keel variable. Axis straight above, 

 often slightly twisted and calloused or truncate below. Aper- 

 ture truncate above, the peristome interrupted there. 

 Arboreal. 



Genus SPIROSTEMMA Pilsbry & Vanatta. 



Spirostemma P. & V., Proc. A. N. S. Phila., 1898, pp. 270, 

 275 (July 12, 1898) ; type " U. rubra C.B.Ad."=. inusitata 

 Vend. Anoma in part, PFR., Nomencl. Hel. Yiv., p. 275 

 (1878). 



The shell is pillar-shaped or cylindric-fusiform, broadly 

 truncate, monochromatic, brown or reddish, striate through- 

 out, dull or hardly glossy ; the last whorl is strongly carinate 

 below, the keel bounding a concave basal area. The aperture 

 is oblique, rounded-ovate, more or less angular at the termi- 

 nation of the keel. The peristome is obtuse and expanded or 

 reflexed, continuous, arcuate and free or adherent above. 

 The internal axis is coiled cork-screw like, at least in the later 

 whorls or the last one. The protoconch is pupiform, with 



