Winclie.U.] 
254 
[Jan. 4, 
Centronella? Flora, n. sp. 
Sliell broadly ovate, rather rectilinear along the cardinal slopes, broadly 
and slightly sinuate, or not, along the ventral commissure ; general form 
of each valve a segment of a sphere. Surface of shell very finely and 
sharply striate both longitudinally and concentrically. 
Length, fifteen-sixteenths of an inch ; breadth, fourteen-sixteenths ; 
thickness of both valves seven-sixteenths. 
This species is broader and less rostrate than G. Allei, Win. (Proc. A. 
FT. S., Phil., July, 1865, p. 128,) and also less tumid around the margins, 
besides being much more distinctly striate. 
Though I am not positive of the generic relations of this species, it ap¬ 
pears to be congeneric with G. Allei. These species are both ornamented 
with beautiful terebratuloid punctations, and both exhibit the elongated 
ribbon-like muscular markings on the ventral valve which also cliarac- 
^ terize the well-determined species G. Julia. In one of the specimens re¬ 
ferred (provisionally) to G ? Flora, there is a low, but elongated median 
septum in the dorsal valve, from which, near the beak, proceeds, on each 
side, a thin horizontal, longitudinal plate, reaching half the length of the 
septum. In the ventral valve, the dental lamellae are feebly developed, 
and, instead of reaching the inner surface of the valve, they curve toward 
! *J ie median line and join each other, leaving a small space between the 
transverse septum thus formed and the surface of the valve—being thus 
a kind of shoe-lifter septum inverted,—or, more strictly, a trough-like plate, 
I as i 11 Gamarophoria, but not, like that, supported by a median vertical 
plate. It is worthy of consideration whether these distinctive characters 
are not of generic importance. The structure noticed in this specimen 
connects Penlamerus with Terebratula, as Gamarophoria connects Penta- 
merus with Rhynchonella. I reserve the subject for further study. 
From bed No. 4, Sciotoville, Ohio. 
Pernopecten ? Cooperersis, Shum. sp. (Mo. Geol. Rep., Pt. ii, p. 
206, pi. C, 15.) Herzer’s collection, Newark, Ohio. 
The single internal cast referred to this species is rather too narrow- 
having about,the form of P. limceformis. It is marked by about fifteen 
coarse radiating grooves, with some traces of smaller intermediate ones. 
Messrs. Meek and Worthen have expressed a strong suspicion (Ill. 
Geol. Rep. Ill, p. 454', that Pernopecten limceformis and P? Shumardian¬ 
us are but varieties of Avicula Gooperensis , Shum. I embrace the opportu¬ 
nity to correct the impression of these authors that the surface characters of 
P. limceformis have not been seen in a perfect state of preservation. I have 
impressions of exteriors of this species upon fine (almost lithographic) 
stone, in which the most delicate characters are much more perfectly pre¬ 
served than they generally are in fossils retaining the actual shell. Gutta 
percha restorations from these moulds are perfectly destitute of fine ra¬ 
diating striae. On the contrary, they exhibit very fine, sharp and regular 
concentric striae, and obsolete traces of a few straggling, irregular, discon¬ 
tinuous, broad folds or undulations. This species is also distinctly nar¬ 
rower than the others. With little doubt, its validity should be admitted. 
