278 TRANSACTIONS OF THE WAGNER FREE 



established have been described from the Haitian Miocene by Gabb, who 

 has given brief diagnoses, but no figures. They are C. dentilabmm, domini- 

 cense, microlineatimi, obesiim, prisniaticum, simplex, siiprasidcahun, turricidum, 

 vemtstiim and Yaqiiensis. C. uniseriale Sowerby, also from Santo Domingo, has 

 been figured by Guppy, and is included in Gabb's list, where C. picttim Wood 

 and C. plebeium Sowerby (the last, with C. obesiim, also figured by Guppy) 

 also find a place. Gabb has also described a C. laeviusaditm from Peru, and 

 a C. mexicamim from the Cretaceous of Sonora. 



These eliminations made, we have left for the Tertiary of the United 

 States only the following-described species : Eocene, C. georgiamim Lyell 

 and Sowerby, from North Carolina ; C. solitarutvi Conrad, C. vinctuni Whitfield 

 sp., C. Whitfield Heilp. and C. {Potamides) toiiibigbeensis Aldrich, from 

 Alabama;' Miocene, C. precursor Yi&\\'^x\n, from the Orthaulax bed, Tampa, 

 Florida ; C. hillsboroensis Heilprin, from the Tampa Orbitolite bed ; Plio- 

 cene, C. ornatissimmn Heilprin and C. atratum Born, from Florida; and a 

 few Post-Pliocene and recent species. To this meagre catalogue, as will be 

 seen, substantial additions will be made in the present paper. 



Oerithium georgianum Lyell and Sowetby. 

 C. georgia?mm L. and S., Quart Journ. Geol. Soc. i. p. 439, 1S45. Figured. 



Uppermost Eocene (or lowest Miocene) bed of Jacksonboro', Scriven 

 County, Georgia ; older Miocene of the Orthaulax bed. Ballast Pt, Tampa 

 Bay, Florida, Ball. 



Two specimens of a fossil which seems to differ but slightly from 

 Sowerby's description in Lyell's paper were found at Ballast Point. Unfortu- 

 nately, the aperture is imperfect in one and wholly wanting in the other. The 

 principal point of difference is that C. georgiajia is described as having 

 "rather obsolete" transverse ribs, while the Tampa specimen has the ribs 

 fairly well marked. But we all know that this, especially in Ceritldum, is a 

 variable character. As Sowerby's description and figure are not accessible 

 to many, 1 give a brief diagnosis of the species. Shell often or more whorls, 

 with about two varices on each, rather regularly disposed on each side of the 

 shell ; between each two varices are 5-7 narrow, flexuous, rounded, little- 

 elevated ribs, which cross the whorls from suture to suture, or may be obsolete 

 in front of the periphery ; the spiral sculpture on the spire is composed of 

 three primary spirals on the middle of the whorl, with wider interspaces, each 

 occupied by a small intercalary thread ; behind the posterior primary spiral 

 are three small threads next the suture ; whorls rounded, suture appressed ; 

 on the base are three or four more primary spirals, which, with the three 

 above the periphery, become much elevated on the last half of the last 

 whorl, while the transverse sculpture on the last whorl is feeble or obsolete; 

 the base and aperture somewhat resemble the same parts in C. innscar-iini Say; 

 where the transverse and spiral sculpture intersect, the spirals, which overrun 



