100 



THE NAUTILUS. 



on each whorl varies considerably, but average about three on the 

 antepenultimate, five on the penultimate, and seven on the ultimate. 

 The spots are equidistant whether considered as forming spiral or 

 longitudinal rows. Whorls 3-4, the first growth being lost. Aper- 

 ture vertical, subcircular, color within corresponding to the outside. 

 Peristome with slightly raised white inner rim, and broad flat white 

 expansion, slightly dilated at the columellar margin, and also above 

 where adnate to the whorl. 



Length 11.5 mm., width 7 mm. 



Length 10.5 mm., width 6.5 mm. 



Operculum white, slightly concave, with involuting lines and 

 deeply grooved edge. The dark central core is nearer the columellar 

 margin than any other portion of the peristome. 



Types : No. 22879, M. C. Z. 



CHONDROPOMA CARIBB^UM, sp. nov. PI. VI, figs. 3, 4. 



Shell subperforate, oblong, truncate, solid, with spiral flattened 

 ridges and more numerous longitudinal lines. Color varying from 

 horn to purple black, remaining whorls 4^, convex, suture deep, 

 nearly simple. Aperture vertical, longer than wide, rounded below, 

 narrowed above. Peristome simple, adnate to the penultimate 

 whorl, upper outer edge slightly broadened and reflexed. 



Operculum cartilaginous, rounded below, broadly pointed above ; 

 whorls few, rapidly enlarging, outer half having edge turned abruptly 

 out, inner edge turned in. 



Length 10.5 mm., diam. 4.5 mm., ap. 3 mm. 



Length 10 mm., diam. 4.5 mm., ap. 3 mm. 



In size and general appearance this shell resembles O. simplex, 

 from Haiti, but the spiral and longitudinal lines are finer and more 

 numerous, and the last whorl is always adnate. 



Types : No. 22885, M. C. Z. 



LUCIDELLA PILSBRYI, Sp. HOV. PI. VI, fig. 6, 7. 



Shell depressed, with elevated, fine, spiral lines, strongest on 

 early whorls, nearly obsolete on rounded periphery, base nearly 

 smooth, or with more or less numerous, delicate, spiral furrows. Spire 

 depressed, whorls 4, the last slighfly deflexed. A thin granular 

 callus extends from the aperture over the umbilical region, ending 

 in a slight depression. Aperture very oblique, peristome white, a 



