FORAMINIFERA OF THE BYEAM CALCAEEOUS MARL AT BYEAM, MISS. 



101 



shown in the figure. Definite placing of these 

 forms under a specific name is left until the 

 study of the various species of our Coastal Plain 

 Tertiary is undertaken. 



Genus LEPIDOCYCLINA GUmbel, 1868. 



LepidocycUna supera (Conrad) H. Douville. 



OrbitoUtes supera Conrad, Acad. Nat. Sci. Philadelphia 



Prof., Xo. 2, p. 74, 18G5. 

 Orhiloides supera Conrad, Am. Jour. Sci.. 2d ser., vol. 43, 



p. 31. 1867. 

 Lepidoryclina supera (Conrad) H. Douvill^, Compt. 



Rend., 1918, pp. 263, 264, figs. 6-8, 11. 

 Cashman, U. S. Geol. Survey Prof. Paper 12-5, p. 69, 



pi. 26, figs. ,5-7, 1920. 



Test flattened or slightly sellaeform, typi- 

 cally circular but occasionally irregular with 

 lobes at one side or elongated oval; thickest 

 in the central region but not distinctly umbo- 

 nate, gradually decreasing in thickness to the 

 periphery; surface apparently smooth but with 

 slight enlargement becoming papillate, the pa- 

 pillae, which are the ends of the pillars, rounded 

 and projecting above the general surface 

 slightly, or where the test is eroded becoming 

 more prominent. Diameter as much as 18 

 millimeters in adult specimens, thickness about 

 2 millimeters. 



This species is abundant in the Byram marl, 

 of which it is one of the index fossils. 



Family MILIOLIDAE. 

 Genus CORNTJSPIRA Schultze, 1854. 

 Cornuspira involvens (Reuss) Reuss. 



Plate XXV, figure 1. 



Operculina involvens Reuss, Akad. Wiss. Wien Denksihr., 



vol. 1, p. 370, pi. 45, fig. 20, 1849. 

 Cornuspira involvens (Reuss) Reuss, .\kad. Wiss. Wieu 

 Sitzungsber., vol. 48, p. 39, pi. 1, fig. 2, 1863 [1864], 

 H. B. Brady, Challenger Rept.. Zoology, vol. 9, p. 200, 



pi. 11, figs. 1-3, 1884. 

 Cashman, U. S. Nat. Mus. Bull. 71, pt. 6, p. 2.':., p). 1, 

 fig. 2; pi. 2, fig. 2, 1917. 



There are but a few specimens of this species 

 in the Byram marl. They are smooth and of 

 small size, only about 0.4 millimeter. 



The species is very widely distributed. It is 

 common in the shoal waters of the Tropics and 

 reaches a large size in the warm waters of the 

 Indo-Pacific region, as, for example, in the 

 Philippines. Elsewhere it seems to be of 

 small size. 



Genus SPraOLOCULINA D'Orbigny, 1826. 

 Spiroloculina grateloupi D'Orbigny. 



Plate XXV, figure 2. 



Spiroloculina grateloupi D'Orbignj', Annales sci. nat., 



vol. 7, p. 298, 1826. 

 Terquem, Soc. g^ol. France Mem., 3d ser., vol. 1, 



p. 52, pi. 5, figs. 5, 6, 1878. 

 Weisner, Archiv Protisten-Kunde, vol. 25, p. 208, 



1912. 

 Cushman, U. S. Nat. Mus. Bull. 71, pt. 6, p. 31, pi. 4, 



figs. 4, 5, 1917. 

 Spiroloculina ercavata H. B. Brady (not D'Orbigny), 



Challenger Rept., Zoology, vol. 9, p. 151, pi. 9, 



figs. 5, i;, 1884. 



The marl from Byi-am contains a number of 

 specimens which seem nearer to this species 

 than to any other. The periphery, however, 

 is not greatly rounded, but the sides of the test 

 are deeply excavated, and there is a strong 

 keel at the outer edge of each chamber, the 

 neck is produced, and the surface is smooth. 

 One specimen exhibits the series of openings at 

 either end of each coil seen in a number of 

 other species. This is a microspheric specimen. 



The species is widely distributed and is 

 especially abundant in the Indo-Pacific, oc- 

 curring in great numbers in certain parts of 

 the Philippine region and elsewhere in shallow 

 warm waters. 



Spiroloculina byramensis Cushman, n. sp. 



Plate XXV, figures 4a, 4b. 



Test compressed, broadly rounded in side 

 view; peripheral margin scjuarety truncate, 

 sides of the chambers sloping in somewhat 

 toward the center, surface with a beautiful 

 ornamentation consisting of fine hexagonal 

 depressed areas M'ith very narrow thin ridges 

 between covering the entire surface. Length 

 0.85 millimeter. 



This is rare in the marl at Byram, but its 

 beautifully ornamented surface is very dis- 

 tinctive. It resembles Tercfuem's figures of 

 Quinqueloculina variolata D'Orbigny, from the 

 Pliocene of the Isle of Rhodes. 



Spiroloculina imprimata Cushman, n. sp. 



Plate XXV, figures 3a, 3b. 



Test broad and flat, complanate, nearly 

 circular in outline, composed of numerous 

 chambers, those of the last-formed coil failing 

 to extend to the base of the preceding chamber, 

 leaving a gap; periphery square, lateral faces 

 nearly flat; the surface ornamented by a 



