163 Midway Stage 49 



impressions numerous about the anterior apical portion of the 

 body cavity, shown in the figure as small elevations about the 

 beak of this internal cast; shell rather thin. 



This species resembles P. bazini Desh. in general, but has 

 different umbonal and ligamental characters and is more oblique. 

 Deshayes species is from the Sables infirieurs of the Paris basin. 



We have felt much hesitation in naming specifically specimens 

 so imperfectly preserved. But the peculiar hinge characters and 

 the interest attached to the discovery of this genus in our Eocene 

 deposits render it doubly advisable to have a name whereby the 

 species may be conveniently referred to. 



Locality. — Railroad cut, i^ miles N. E. of Clayton, Barbour 

 Co., Ala. 



Type. — Paleontological Museum, Cornell Univ. 



MODIOLA. 

 Modiola subpontis n. sp., Pi. 3, figs. 6, a. 



Specific characterization. — General form as shown by the figure 

 — twice natural size; very gibbous especially about the umbones 

 which are incurving and resemble those of Lithodomus gainesensis; 

 surface marked by strong, bifurcating, radiating lines like those 

 of many members of this genus; near the umbones the lines are 

 less distinct. This shell is found in the burrows or within the 

 shells of Gastrochcena or Lithodomus. The one figured was broken 

 out of an L. gaiyiesensis a part of which is shown in the figure. 

 A portion of the exterior of this individual is shown in fig. 6, a. 



Locality. — Uppermost layer of the Midway limestone as ex- 

 posed at Ft. Gaines, Ga. Rare. 



Type. — Paleontological Museum, Cornell Univ. 



Modiola saffordi, PI. 3, fig. 4, 5. 



Syn. M. saffordi Gabb, Jr. Ac. Nat. Sci., vol. iv, i860, p. 

 395, pi. 68, fig. 30. 

 M. saffordi Saff., Geol. Tenn., 1869, p. 419. 



Gabb's original description. — "Gibbous, widened posteriorly; 

 beaks small, anterior; umbones very large; umbonal ridge 

 prominent, rounded, with a rounded furrow anterior to it; cardi- 

 nal margin nearly straight, posterior margin rounded, basal sinu- 

 ous; surface marked by regular radiating ribs, except a small 

 space between the umbonal ridge and the beak, leaving a little 

 more than one-third of the basal portion plain, or only marked 



