INSTITUTE OF SCIENCE, PHILADELPHIA. 371 



triseriata Say, but with a larger, though somewhat variable, umbilicus. It is 

 more elevated and larger than perspecta, and almost invariably has a little 

 notch or groove on the upper reflected part of the pillar. L. decipiens Meyer 

 (1885) and probably/^, marylandica Conrad (1865) are synonyms. The latter 

 is doubtfully from Maryland. We have L. vicksbttrgensis irom many \ocay\\.\es 

 in the Vicksburg beds in Mississippi, and from Alabama, White Bluff, Arkan- 

 sas, the Prairie Creek beds and the Jacksonian. One of our specimens has 

 had the aperture symmetrically filled up, leaving a central opening of uniform 

 caliber, as in Mr. Aldrich's Expleritoma and Dr. Meyer's Castellum. From 

 the close similarity of the operation to the work of certain recent Annelids, 

 which fit dead shells for their habitations in this manner, I am convinced that 

 these Eocene shells have been similar harbors of refuge, and consequently 

 that we shall have to give up the genera founded on this state of things. The 

 thickening is done so evenly and neatly that it is difficult to detect the junc- 

 tion between the secretions of the Annelid and the Mollusk respectively, but 

 in the recent shell they are at once distinguishable by their color. 



L. parva Lea is a curiously elongated species with appressed whorls, and 

 notable for its deep, narrow umbilicus, carinated at the outer margin, and the 

 pillar thin and excavated by the umbilicus. It never reaches the size of the 

 last species. Conrad's A'', eminula doubtless belongs here, but De Gregorio's 

 N. parva is another species, probably a variety of N. minor Lea. L. parva 

 is a characteristic Claibornian fossil. I have seen it also from White Bluff, 

 Jefferson County, Ark., and from the Eocene of the Sepulga River, Alabama. 



There are several undescribed forms in the Prairie Creek beds Heilprin 

 has described a N. Dumblei, probably a Lunatia, from the Eocene of Texas. 

 According to Prof Heilprin, L Moorei Gabb is founded on a small specimen 

 of N. minor Lea. Natice eborea Conrad (in Morton, Syn. Org. Rem.) is 

 Dillwynella naticoides Lea. N. lisbonensis h\Ax\z\\ I have not seen. 



The Miocene species are less numerous, yet the group is well represented, 

 and the shells are of considerably larger size in most cases. 



Polynices (Lunatia) hemicryptus Gabb. 



Natica hemicrypta Gabb, Journ. Acad. Nat, Sci. Phila., 2d Series, iv. p. 375, pi. 67, fig. 5, 

 i860 ; Conrad, Am. Journ. Conch, iv. p. 66, pi. 6, fig. i (fig. 7 excl.), 1868 ; Whitfield, 

 Gastr. N. J. Miocene Marls, pi. 22, figs. 1-5. 



Lunatia eminuloides Gabb, Journ. Acad. Nat. Sci. Phila., 2d Ser. viii. p. 339, pi. 44, fig. 4, 

 1875. 



Not N. hemicrypta- ConrSid, Am. Journ. Conch, iv. pi. 6, fig. 7, i868. 



? Natica caroliniana Tuomey and Holmes, Pleioc. Fos. S. C, pi. 25, fig. 18. 



Older Miocene of Shiloh and Jericho, N. J., Gabb and Burns ; Oi the 

 Chipola beds near Bailey's Ferry, Chipola River, Calhoun Co., Florida, of the 

 Orthaulax bed at Ballast Point, Tampa Bay, Florida ; and of Sapote, Costa 

 Rica, Gabb, 



This small species, first described by Gabb, was afterward confounded 



