FORAMINIFERA OF THE ATLANTIC OCEAN 53 



1916-17 (1920), p. 56.— CusHMAN, 13th Ann. Rcp't. Florida Geol. Survey, 

 1921, p. 52; Bull. 100, U. S. Nat. Mus., vol. 4, 1921, p. 339, pi. 71, figs. 

 1 a-c. — Clodius, Archiv. Ver. Freunde Nat. Mecklenburg, 75 Jahr., 1922, 

 p. 136.— Heron-Allen and Earland, British Antarctic Exped., Zoology, 

 vol. 6, 1922, p. 216.— Martinotti, Atti Soc. Ital. Sci. Nat., vol. 62, 1923, 

 p. 351, pi. 7, figs. 65-67. — Chapman, New Zealand Geol. Survev, Pal. 

 Bull., No. 11, 1926, p. 84, pi. 17, fig. 3. 



Eponides umhonata Cole, Bull. Amer. Pal., vol. 14, No. 53, 1928, p. 215 (15), 

 pi. 2, fig. 6. — Ctjshman, Contr. Cushman Lab. Foram. Res., vol. 5, 1929, 

 p. 98, pi. 14, figs. 8 a~c. 



Rotalia umhonata Galloway and Morrey, Bull. Amer. Pal., vol. 15, No. 55, 

 1929, p. 26, pi. 4, figs. 1 a-c. 



Truncaiulina tenera H. B. Brady, Rep. Voy. Challenger, Zoology, vol. 9, 

 1884, p. 665, pi. 95, figs. 11 a-c. — Egger, Abhandl. kon. bay. Akad. Wiss. 

 Munchen, CI. II, vol. 18, 1893, p. 402, pi. 16, figs. 45-47.— Chapman, 

 Proc. Zool. Soc. London, 1895, p. 41. — Dakin, Rep't. Pearl Oyster Fish. 

 Ceylon, 1906, p. 238. — Chapman, Journ. Linn. Soc. Zool., vol. 30, 1910, 

 p. 421. — Pearcey, Trans. Roy. Soc. Edinburgh, vol. 49, 1914, p. 1027. — 

 Chapman, Biol. Res. Endeavour, vol. 3, 1915, p. 30. — Cushman, Bull. 

 71, U. S. Nat. Mus., pt. 5, 1915, p. 37, pi. 16, fig. 2; pi. 23, fig. 6.— Chap- 

 man, Rep't. British Antarctic Exped. Geol., vol. 2, 1916 (1917), p. 70, pi. 

 4, fig. 38. — SiDEBOTTOM, Joum. Roy. Micr. Soc, 1918, p. 257. — Halk- 

 YARD, Mem. Proc. Manchester Lit. Philos. Soc, vol. 62, pt. 2, 1918 

 (1919), p. 118.— Cushman, Bull. 100, U. S. Nat. Mus., vol. 4, 1921, p. 318, 

 pi. 64, figs. 2 a-c. — Heron-Allen and Earland, British Antarctic Exped., 

 Zool., vol. 6, 1922, p. 211.— Hanzawa, Jap. Journ. Geol. Pal., vol. 4, 

 1925 (1926), p. 43. — Yabe and Hanzawa, Jap. Journ. Geol. Pal., vol. 4, 

 1925 (1926), p. 52.— Chapman, New Zealand Geol. Survey, Pal. Bull., No. 

 11, 1926, p. 78, pi. 15, figs. 14a,6.— Plummer, Bull. 2644,Univ. Texas, 

 1927, p. 146, pi. 9, figs. 5 a-c. 



Rotalia ecuadorensis Galloway and Morrey, Bull. Amer. Pal., vol. 15, 

 No. 55, 1929, p. 26, pi. 3, figs. 13 a-c. 



Test biconvex, varying much in relative amount in different speci- 

 mens, periphery acute to rounded ; chambers distinct, from five in the 

 young and megalospheric forms to eight in the adult microspheric form, 

 very little inflated, increasing uniformly in size as added; sutures 

 distinct, those of the dorsal side in the young straight and nearly 

 radial, in the adult slightly oblique, on the ventral side usually with 

 a characteristic sigmoid curve; wall smooth, very finely perforate;, 

 aperture usually about midway between the periphery and umbilical 

 region of the ventral side, often with a slightl}^ thickened border or 

 even a slight lip. 



Diameter up to 1.10 mm. in the microspheric form. 



This is a widely distributed species of comparatively long range, 

 appearing early in the Tertiary and widely distributed in the present 

 oceans. Reuss originally described it from the Oligocene of Germany 

 where it is often very abundant. It has occurred commonly in some 

 of the Albatross dredgings as recorded in the accompanying table. 



There is apparently a wide range of variation in some of the char- 

 acters but this may be due to age and the microspheric and megalo- 



