CHILONOPSIS. 179 



Length 15.5, diam. 5.3 mm. ; aperture 6 mm. 



Length 14, diam. 5 mm.; aperture 5.6 mm. 



St. Helena: fossil in a cutting through surface soil on the 

 Sidepath, between Jamestown and Longwood, on the side of 

 the hill overlooking the Briars (Wollaston) ; Sugarloaf Ridge, 

 common (Turton). 



Cochlicopa subplicata Sows, in Darwin's Geological Ob- 

 servations on the Volcanic Islands, etc., Appendix, p. 156 

 (1844). Bulimus subplicatus Sowerby, FORBES, Quart. 

 Journ. Geol. Soc. Lond. viii, 1852, p. 199, pi. 5, f. 6. 

 Subulina subplicata WOLL., Testae. Atlant. p. 552. Buli- 

 mulus (Peronceus f) subplicatus (Sowerby), SMITH, P. Z. S. 

 Lond. 1892, p. 266, pi. 22, f. 15Pachyotus s., DALL, Proc. 

 A. N. S. P. 1896, p. 419. Cochlicopa terebellum SOWB., t. c. 

 p. 156. Bulimus t., FORBES t. c. p. 199, pi. 5, f. 5. Subulina 

 t., WOLLASTON, t. c. p. 552. 



Var. terebellum Sowerby. (PI. 52, fig. 52). " Shell ob- 

 long, cylindric-pyramidal, the apex rather obtuse; whorls 7, 

 smooth; suture posteriorly crenulate. Aperture oval, acute 

 posteriorly, the outer lip thin, sloping in front. Columella 

 obsoletely truncate, umbilicus small. Length .77, diam. .25 

 inch. This species differs from the last [subplicatus] in be- 

 ing more cylindrical and in being nearly free when full grown 

 from the obtuse folds of the posterior volutions, as well as the 

 form of the aperture. The young shells of this species are 

 longitudinally striated, and they have some very obsolete 

 folds" (Sow*.). 



This is evidently a form of C. subplicatus. The original 

 description is given, and a copy of Forbes' figure of the type, 

 collected by Darwin. 



Subgenus CLEOSTYLA Dall, 1896. 



Proc. A. N. S. Phila. 1896, p. 419, in text. 



The oval or oblong shell is thin, smoothish, not plicate be- 

 low the suture; the outer lip is thin and somewhat expanded 

 below. The smooth apical whorls form a slightly mamillar 

 summit. Type C. exulatus Bens. 



While without bosses below the suture, C. exulatus has 



