INSTITUTE OF SCIENCE. PHILADELPHIA. 345 



Gabb {pp. cit. p. 368, pi. 47, fig. 68), from Santo Domingo, are merely very- 

 young examples of varieties of this species. Vitrinella viarginata Guppy, from 

 the Pliocene of Trinidad, with which Gabb compares one of his shells, is too 

 badly figured to be identified, but may be an Adeorbis, though the figure looks 

 more like a Solariorbis , and does not agree with the description. 



Adeorbis Beaui Fischer. 



Adeorbis .5<?(z«t Fischer, Journal de Conchyl. vi. p. 286, pi. 10, fig. 12, 1857. 

 Cyclostrema bicarinatum Guppy, Quart. Journ. Geol. Soc. xxii. p. 291, pi. xvii. figs. 5 a, 

 5 b, 1866. 



Older Miocene of Jamaica (Guppy) and of Santo Domingo (Gabb) ; living 

 from Florida to Guadelupe, West Indies. This species has not been reported 

 from our southern Tertiaries, but can hardly fail to exist there, and should be 

 searched for. It is a repetition of the preceding species on a very much 

 larger scale. 



Adeorbis obliquistriatus H. C. Lea. 



Delphinula obliquistriata H. C. Lea, Trans. Am. Phil. Soc, 2d Ser. ix. p. 261 (extra copies 

 P- 35), pl- 36, fig- 72, 1845. 



Chesapeake Miocene of Petersburg, Va., Lea. 



This little shell has somewhat the aspect of a Molleria, but should per- 

 haps be referred to Adeorbis. 



Adeorbis strigillatus n. s. 

 Plate 19, figures 10, 10 b. 



Pliocene of the Caloosahatchie beds; Dall. 



Shell small, flattened, of four whorls ; nucleus extremely minute, smooth ; 

 spire depressed; suture distinct, not channelled ; the whorl excavated spirally, 

 parallel with and close to the suture ; periphery keeled ; the top of the whorl 

 between the periphery and the channel next the suture rounded, rather promi- 

 nent; upper surface of the whorls variable, from smooth to strongly radiately 

 ribbed with flexuous costse ; base flattish, with two strong spiral keels and 

 one at the margin of the umbilicus; between these keels narrow, flexuous, 

 elevated threads radiate from the umbilical margin, but do not crenulate the 

 keels, and vary in strength with different individuals, though never quite obso- 

 lete ; in the interspaces between the keels there are sometimes one or two fine 

 intercalary spirals ; umbilicus deep, subcylindrical, with smooth sides ; aper- 

 ture rounded, the outline modified by the keels, a slight callus on the pillar 

 lip, otherwise the edge is sharp and simple. Alt. i.o; max. diam. 2.0 mm. 



This little shell belongs to the group of A. sjtbcarinahis, and, in spite of 

 the variability which we have referred to, manages to preserve a very recog- 

 nizable individuality. 



