NO. 1785. WEST AMERICAN VITRINELLID8—BART8GH. 231 



CYCLOSTREMA ADAMSI, new species. 

 Plate 39, figs. 4-6. 



Shell very small, depressed helicoid, white. Nuclear whorls two 

 and a third, smooth, well rounded. Post-nuclear whorls one and a 

 third, very strongly sculptured, having a slender, spiral, nodulose 

 keel at the summit, an exceedingly strong one at the periphery, and 

 two others almost as strong as the peripheral keel in the space be- 

 tween the summit and the periphery. The space between the peri- 

 pheral and the supraperipheral is a little wider than the space between 

 the cord at the summit and the keel anterior to it, while the space 

 between the second and third keels is about twice as wide as that 

 between the cord at the summit and the second keel. In addition to 

 these nodulose keels, the whorls are marked by strong, retractive, axial 

 ribs, of which twenty occur upon the last turn. The junctions of 

 the ribs and keels form prominent tubercles, while the spaces inclosed 

 by them are deep, rhomboidal pits. Those occurring between the 

 peripheral and the first supraperipheral keel are about as long as 

 broad, while those between the next two keels, posteriorly, are much 

 longer in their axial diameter than their spiral, and those occurring 

 between the summit and the first keel below it, are a little longer in 

 the axial diameter than the spiral. Base of the shell openly umbili- 

 cated, marked by two strong, nodulose keels, the weaker of which 

 bounds the umbilicus, while the stronger is half-way between this 

 and the peripheral keel. The axial ribs extend prominently over 

 the base to the umbilical keel, renderuig the middle keel strongly 

 tuberculate. The spaces mclosed between the keels and ribs are 

 quadrangular immediately below the periphery, and wedge-shaped 

 between the median and the umbilical keel. Umbilicus narrowl}^ 

 funnel-shaped. Aperture subcircular; peritreme complete, stout, 

 thinning to a slender edge. 



The type (Cat. No. 211563, U.S.N.M.) comes from Panama and 

 measures: greater diameter, 1.3 mm. 



It is named for C. B. Adams. 



CIRCULUS LIRIOPE, new species. 



Plate 40, figs. 7-9. 



Shell small, depressed, helicoid, creamy-white. Nuclear whorls 

 two and a third, smooth, well rounded, separated by a w^ell-marked 

 suture. Post-nuclear whorls well rounded, appressed at the summit, 

 with a strong keel at the periphery and a less strong one on either 

 side of the periphery, these two appearing as if joined to the periph- 

 eral keel by a smooth band, the whole having the effect of a thick 

 ribbon drawn over the peripheral keel, with the two edges rolled up 

 to form the other two keels. The entire upper surface is marked by 



