FORAMINIFERA OF THE ATLANTIC OCEAN. 



125 



Mem. Pont. Accad. Nuovi Lincei, vol. 12, 1896, p. 104, pi. 2, figs. 11, 12.— 

 I<YiKT, Rep. V. S. Xat. Mus., 1897 (1899), p. 292, pi. 38, fig. 3.— Morton, 

 Proc. Portland See. Nat. Hist., vol. 2, 1897, p. 116, pi. 1, fig. 12.— Millett, 

 Journ. Roy. Micr. Poc, 1901, p. 2. — Whiteaves, Geol. Survey Canada, 1901, 

 p. 10. — KiAER, In Due d 'Orleans, Croisi^re Oc^n, Mdr du Gronland, 1905 

 (1907), p. 560.— Earland, Journ. Quekett Micr. Club, ser. 2, vol. 9, 1905, p. 

 209.— Bagg, Proc. U. S. Nat. Mus., vol. 34, 1908, p. 139.— Sidebottom, Mem. 

 Proc. Manchester Lit. Philos. Soc, vol. 54, 1910, p. 14.— Chapman, Journ. 

 Linn. Soc. Loudon, vol. 30, 1910, p. 405. — Awerinzew, Mem. Acad. Imp. 

 Sci., St. Petersburg, ser. 8, vol. 29, No. 3, 1911, p. 18.— CushmanBuH. 71, 

 U. S. Nat. Mus., pt. 2, 1911, p. 97, fig. 151a, b, c (in text).— Heron-Allen 

 and Earland, Proc. Roy. Irish Acad., vol. 31, pt. 64, 1913, p. 70. — Pearcey, 

 Trans. Roy. Soc. Edinburgh, vol. 49, 1914, p. 1015. — Heron-Allen and 

 Earland, Journ. Roy. Micr. Soc, 1916, p. 44; Trans. Linn. Soc. London, 

 vol. 11, ser. 2, 1916.— Sidebottom, Journ. Roy. Micr. Soc, 1918, p. 128.— 

 CusHMAN, Bull. 100, U. S. Nat. Mus., vol. 4, 1921, pi. 172. 



Cassidulina laevigata h'Orbigi^y, var. crassa Parker and Jones, Philos. Trans, 

 vol. 155, 1865, p. 377, pi. 15, figs. 5-7; pi. 17, fig. 64(/. 



Cassidulina obtusa Wit.liajison, Rec. Foram. Great Britain, 1858, p. 69, pi. 6, 

 figs. 143, 144. 



Description. — Test subcircular, but oval in outline, biconvex, the 

 peripheral border l)roa(ily rounded; chambers c^omparatively few, 

 short, and inflated; wall calcareous, perforate, smooth; sutures dis- 

 tinct, somewhat depressed; aperture a long narrow slit just below 

 and nearly parallel to the periphery of the test, often with a long 

 tooth, partially filling the aperture; color white or light brown. 



Length 0.60-1.0 mm. 



T)istrihittion.—L\ke the preceding species this is very v/idely dis- 

 tributed, but appears to be found more often in shallow water than 

 C. laevi(iat<i. It is recorded from numerous stations off the British 

 Isles, in the North Sea, off Greenland, and in the Gulf of the St. 

 Lawrence. There are numerous stations in the Albatross material 

 from the Atlantic coast of the United States and in the Gulf of 

 Mexico. In shallow water, and especially in Casco Bay, Maine, a small 

 thick form of the species occurs. This has a rougher surface than 

 the typical form of deep water. In the examination of the Atlantic 

 specimens I have had it is impossible to distinguish C. crassa from 



C ohionfia. 



Cassidulina crassa — material examined. 



