1920.] NATURAL SCIENCES OF PHILADELPHIA. 205 



tical, with a raised, smooth rim in advance of the broadly expanded, 

 flat, white Hp, which is provided with several, slightly raised, con- 

 centric lamellae; outer lip forming at the suture a recurved hollow 

 tube connecting the deep suture openly with the interior of the aper- 

 ture by a small round pore. The broadly expanded basal and col- 

 umellar lips showing faint white thickenings at the ends of the above- 

 mentioned spirals; parietal hps expanded into a broad flat plate 

 with its edge attached to the body-whorl, the concentric lamellae 

 upon its surface are interrupted in an oblique line above the pore 

 in the aperture, forming a small bay in the upper edge near the outer 

 lip. Operculum, thick, calcareous, paucispiral, smooth within, com- 

 posed of about three rapidly increasing volutions; nucleus below 

 the middle; outer surface with a deep spiral groove with a raised 

 irregular edge arising near the nucleus, continuing along the suture 

 and completely around the outer edge of the operculum; the surface 

 is also covered with coarse raised lamellae in the direction of the lines 

 of growth. 



Alt. 11.2, diam. 6.3, alt. of aperture 5.0, diam. 4.4 mm. 



The types are in the cabinet of the Academy, being tray number 

 44,488, collected at Nassau, New Providence, Bahama Islands, by 

 Mr. C. J. Maynard in 1888. 



One specimen has the apex almost entire and is composed of 

 about seven whorls; another (fig. 11) which is not quite mature, has 

 a broad open bay at the upper angle of the aperture disconnecting 

 the parietal wall and outer lips, and lacks the raised rim about 

 the inner edge of the mouth; some specimens are uniform greyish 

 yellow. 



This species differs from Opisthosiphon hohamensis (Shutt.) by 

 being smoother, having weaker, more spaced vertical costae, finer 

 crenulations at the suture, and a wider expanded lip; 0. moreletiana 

 (Pet.) has stronger costae, and the aperture is free from the body 

 whorl; 0. excurrens (Gundl.) is more strongly costate, obese and 

 cyHndrical. 



Helicina abbotti new species. PI. VI, figs. 12, 14. 



Shell small, globose, moderately thick, opaque yellowish corneus; 

 apex obtuse; spire elevated, conic, composed of four arcuate whorls; 

 suture moderately impressed, not descending at the aperture; per- 

 iphery convex; surface smooth, shining, with a few oblique lines 

 and incremental striae crossed by very indistinct spiral lines \isible 

 under a lens. The base is rather flat, carinate about the edge of 



