346 PROCEEDINGS OF THE ACADEMY OF [April, 



n. subsp. (PL 24, figs. 1,2), has the same comparatively large embryo, 

 but the first sculptured whorl has about 16 more numerous, much 

 narrower ribs. On the last whorl the spirals are equal, without spiral 

 threads in the intervals. The callus does not extend forward from the 

 aperture quite so extensively. 



Length 30, diam. 18 mm. 



Cancellaria barretti Guppy, which is very similar in appearance, has 

 more spiral cords and more lirse within the outer lip. 



Cancellaria decaptyx «• sp. PI. XXIV, figs. 5, 6. 



A small, slender species, composed of 7 whorls in a length of 11 mm. 

 The first 2\ whorls form a smooth naticoid embryonic shell; then 

 three spiral cords appear, and soon after coarse, rounded longitudinal 

 ribs. The spirals increase rapidly in number on succeeding whorls. 

 They pass over the ribs, upon the crests of which they are slightly 

 strengthened. The ribs are not quite as wide as their intervals. 

 On the last whorl there are ten, on the preceding nine ribs. Whorls 

 strongly convex. The aperture is small. Columella with two moderate, 

 oblique folds, which are somewhat receding, being only weakly visible 

 in a front view. 



Length 11, diam. 5 mm. 



We find no closely related species in the American tertiary. 



MITRID^J. 

 Mitra longa Gabb. PI. XXIV, fig. 11. 



M. longa Gabb, Geol. of Santo Domingo, p. 219. 

 The specimens agree well with Gabb's types of this species. As it 

 has not been illustrated, we figure one of the Gatun specimens. It 

 measures, length 37, diam. 9.1 mm. 

 Mitra dariensis n. sp. PL XXIV, fig. 9. 



A species closely related to M. longa, but shorter, the diameter 

 contained about three times in the length. The apex is lost, 6J whorls 

 remaining. These are rather convex, with sculpture of four strong 

 equal spiral ridges, and a smaller thread just below the suture; and 

 on the last three whorls another thread appears between the first and 

 second of the spiral cords. The last whorl has twelve major spirals, 

 and about six small, subequal spirals on the siphonal fasciole. The 

 interstices are sculptured with rather close, sharp longitudinal threads, 

 and in each a spiral sunken line revolves. The aperture is narrow. 

 Columella with four strongly oblique folds, the lowest one very small, 

 upper fold much the strongest. 



Length 22, diam. 7 mm. (apex wanting). 



