438 Systematic Paleontology 



permit the opening and closing of the valves. Each plate seems to be 

 made up of a bundle of filaments, and it is this feature that warrants the 

 conclusion that their presence is due to the postero-lateral setfe and ex- 

 tensions of the pallium. Of course the set£e could not deposit the cal- 

 careous matter to form the fimbria, but this was accomplished by ex- 

 tensions from the pallium, as were the cardinal spines of Chonetes and the 

 ventral spines of Productus. 



Length 11 mm.; width 12 mm. 



Occurrence. — Obiskany Foematiox, Eidgely Member. Cumberland, 

 North Branch, Collier's Kun. 



Collections. — Maryland Geological Survey, U. S. jSTational Museum, 

 American Museum of Natural History-. 



Anoplotheca (Leptoccelia) elabellites (Coni'ad) 

 Plate LXXIII, Figs. 29-33 



Atnjpa flabellites Conrad, 1841, Fifth Ann. Rept. N. Y. Geol. Surv., p. 55. 

 Leptocalia flabellites Hall, 1859, Nat. Hist. N. Y., Pal., vol. iii, p. 449, pi. 



cvi, figs, la-1/; pi. ciiib, figs, la-l^, 1861. 

 Anoplotheca flabellites Schucliert, 1897, Bull. U. S. Geol. Surv., No. 87, pp. 



144,145. 



Description. — " Suborbicular, compressed ; ribs about thirteen, rounded ; 

 the two middle ribs of the flat valve largest and rectilinear rather distant 

 at the base from the others, and separated by a deep interstice which 

 produces a sinuous margin; middle of inferior valve depressed towards 

 the base, the three middle ribs larger than the others." Conrad, 1841. 



" Shell somewhat semielliptical, varying to suborbicular or transversely 

 oval, generally broader than long. Ventral valve convex, most prominent 

 along the middle, declining laterally : beak incurved, with a small round 

 perforation in the extremity,- which is completed on the lower side by the 

 two deltidial pieces ; or, in the absence of these, the foramen is completed 

 by the umbo of the dorsal valve. Dorsal valve flat: beak straight; hinge 

 sloping from the beaks at an angle of 110° to 160°, rounded at the ex- 

 tremities. Surface marked by ton to fourteen simple angular plications ; 

 two of which, on the middle of the ventral valve, are a little larger and 



