1896.] .NATURAL SCIENCES OF PHILADELPHIA. 23 



general view, the girdle appears light olive with an ill-defined dusky 

 bar opposite each valve. 



Length 18, breadth 9 mm. (exclusive of girdle). Angle of di- 

 vergence 119°. 



Panamic region, exact locality not known. 



Specimens of this elaborately sculptured Ischnochiton were re- 

 ceived from Mr. W. J. Raymond some years ago. Mr. E. R. Sykes, 

 of London, has kindly compared it with the type of/, dispar Sowb., 

 and informs me that it is quite distinct, confirming the opinion I 

 had already formed from a study of the description and figures of 

 that species. From other West American species it is readily dis- 

 tinguished by the peculiar sculpture, dorsal keel and the coloration 

 of the girdle scales. 



Sagda (?) Gabbi n. sp. 



Shell depressed, with low, conoid-convex spire, round periphery 

 and somewhat flattened, convex base, rather deeply indented around 

 the minute umbilical perforation ; solid though rather thin ; whitish 

 corneous or faintly buflf; the surface rather dull though shining, 

 smooth except for irregular, very faint growth-marks. Whorls 

 about 5i, convex, slowly widening, the last decidedly wider, not 

 descending in front. Suture impressed and narrowly translucent- 

 margined below. Aperture subvertical, a little oblique, lunate ; 

 peristome evenly curved, sharp-edged, the columellar margin lined 

 with white callus inside, and reflexed in the vicinity of the umbilical 

 perforation, nearly concealing it. 



Alt. 7, greater diam. 11, lesser diam. 10 mm. (Type). 



Alt. 8, greater diam. 12, lesser diam. 10'8 mm. (specimen in Pon- 

 souby Coll.). 



San Domingo (W. M. Gabb !). 



Compared with Helix effusa Pfr. (Monographia, V, p. 105, Tryon, 

 Manual II, p. 163), of which part of the original lot collected by 

 Smith are before me, this species is more solid, with smaller perfor- 

 ation, smoother surface and fewer, more rapidly widening whorls ; 

 but it is especially distinguished by the different form of the peris- 

 tome. In effusa the basal lip (in a ventral view of the shell) is seen 

 to bend forward in a broad convex lobe, the outer point of the curve 

 extending as far forward as the insertion of the outer lip ; and upon^ 

 the base the usual direction of the arcuate growth-lines is reversed. 

 In the new species, while there is a slight bend, no such effuse con- 

 dition of the basal lip is developed. 



