1912.] NATURAL SCIENCES OF PHILADELPHIA. 509 



Sigaretus (Eunaticina) gabbi n. sp. PI. XXII, fig. 13. 



The shell is narrowly umbilicate, semiglobose, with very short, 

 narrow spire of 3| whorls. The first two whorls, which compose 

 the embryonic shell, are convex, smooth, and glossy and increase 

 slowly. After that the shell abruptly becomes dull, with sculpture 

 of close, fine, spiral striae. The last whorl is most convex below the 

 periphery. The aperture is nearly as long as the shell, ovate. 

 Columella somewhat thickened and a little rolled back. 



Greatest length 6.5, diam. 6.5 mm.; length of aperture 6 mm. 



Gatun Locks. 



S. multilineatus Gabb from Sapote, Costa Rica, is a larger shell 

 with more conic, elevated spire. 



Bittium scotti n. sp. PI. XXII, figs. 11, 12. 



Shell turreted, with very slightly convex outlines, tapering to a 

 minute, acute apex. Whorls about 12, the first 2 or 3 smooth. 

 Subsequent whorls have sculpture of axial ribs about equal to their 

 intervals, crossed by numerous unequal spiral threads. On the 

 penultimate whorl there are about 15 axial ribs crossed by about 

 6 spiral threads and some minute striae. On the last whorl there 

 are one or two rounded varices, broader and more prominent than 

 the ribs, which are very weak in their vicinity, and do not extend 

 below the periphery. The base has 4 or 5 strong, continuous 

 spiral cords. 



Length 10.5, diam. 3.8 mm. 

 9.5 " 3.6 " 

 8.5 " 2.8 " 



About 65 to 80 feet below the Pecten bed at Tower N, Culebra 

 Cut, near Las Cascades. 



This shell stands close to Bittium boiplex Dall, of the Chipola 

 Oligocene, which differs chiefly by its more slender contour. B. 

 priscum Dall, of the Tampa Silex bed, seems to be an allied form 

 with fewer spirals. B. Scotti is extremely abundant in the friable 

 ignitic bed at Tower N } Culebra Cut, but most of the specimens 

 are calcite pseudomorphs and cannot be extricated from the similar 

 material in which they are imbedded. 

 Turbonilla (Chemnitzia) bartschiana n. sp. Text fig. 4a. 



The shell is minute, slender, with a bulimoid embryonic shell 

 of about 2 smooth whorls, the last strongly convex and nearly 

 half immersed in the first neanic whorl; post-embryonic whorls 6, 

 convex, with sculpture of smooth, rounded, vertical, axial ribs equal 

 to their intervals. On the penultimate whorl there are 17 ribs. 



