2G6 SYSTEMATIC PALEONTOLOGY 



Maximum diameter, 4.6 mm. ; height, 1.2 mm. 

 Occurrence. — Calvert Formation. Plmii Point. 

 Collection. — U. S. N"ational Museum. 



Family CYCLOSTREMATID/E. 



Genus MOLLERIA Jeffreys. 



MOLLERIA MINUSCULA Dall. 



Plate LXII, Fig. 7. 



MoUeria minuscula Dall, 1892, Trans. Wagner Free Inst. Sci., vol. iii, pt. ii, p. 431. 



Description. — " Shell very small, with the general form of Lunatia 

 interna Say, turbinate, fully rounded, with two and a half whorls ; surface 

 smooth, suture distinct, not deep; base rounded; umbilicus very small; 

 aperture rounded, hardly thickened, the margin internally with a percep- 

 tible ledge for the edge of the operculum." Dall, 1892. 



No specimen except the type has been found, but the species is so small 

 that very careful search should be made for it. 



Height, 0.7 mm. ; diameter, 1.0 mm. 



Occurrence. — St. Mary's Formation. St. Mary's Eiver. 



Collection. — U. S. National Museum. 



Superfamily ZYGOBRANCHI A. 



Family FISSURELLID/E. 



Subfamily EMARGINULIN/E. 



Genus FISSURIDEA Swainson. 



FissuRiDEA ALTicosTA (Conrad). 



Plate LXIII, Figs, la, lb. 



Fissurella alticosta Conrad, 18.34, Jour. Acad. Nat. Sci. Phila., vol. vii, 1st ser., 



p. 142. 

 Fissurella alticosta Conrad, 1845, Fossils of the Medial Tertiarj', No. 3, p. 78, pi. 



xliv, fig. 7. 

 Fissurella alticosta Conrad, 1868, Proc. Acad. Nat. Sci. Phila., vol. xiv, p. 570. 

 Fissurella alticostata Meek, 1864, Miocene Check List, Smith. Misc. Coll. (183), 



p. 14. 

 Fissuridea redimicula var. alticosta Dall, 1892, Trans. Wagner Free Inst. Sci., vol. 



iii, pt. ii, p. 425. 



