FORAMINIFEBA OF THE ATLANTIC OCEAN. 95 



Genus AMMODISCUS Reuss, 1861. 



Operculina (part) d'Orbigny, in De la Sagra, Hist. Fis. Pol. Nat. Cuba, 1839, 



p. 49. 

 Orbis Strickland, Quart. Journ. Geol. Soc, vol. 2, 1848, p. 30 (not Orhis of 



Phi li ppi-Comiisp ira) . 

 SpiriUina Williamson, Rec. Foram. (Jreat Britain, 1858, p. 93 (not Spinllina 



Ehrenberg, 1841). 

 Trocharnmina (part) Jones and Parker, Quart. Journ. Geol. Soc, vol. 16, 1860, 



p. 304. — W. B. Carpenter, Parker, and Jones, Introd. Foram., 1862, 



p. 141. 

 Ammodiscus (part) Reuss, Sitz. Akad. Wiss. Wien., vol. 44 (1), 1861 (1862), p. 



365 {Type, A. incertus (d'Orbigny)). — Butschli, in Eronn, Klasaen und 



Ordnungen des Thierreichs, vol. 1, 1880, p. 189. — II. B. Brady, Rep. Voy. 



Challenger, Zoology, vol. 9, 1884, p. 329. — Riiumbler, Naclir. Ges. Wiss. 



Goltingeu, 1895, p. 84. — Eimer and Fickert, Zeitschr. Wiss. Zool., vol. 65, 



1899, p. 614.— Riiumbler, Arch. Prot., vol. 3, 1903, p. 280.— Cushman, 



Bull. 71, U. S. Nat. Mus., pt. 1, 1910, p. 73.— Rhumbler, Foram. Plankton 



Exped., pt. 2, 1913, p. 387. 

 Comuspira (part) Reuss and various authors (not Cornuspira Schultze). 

 Involutina (part) Terquem, M4m. Acad. Imp. Metz, 1860-61 (1862), p. 450; 



1862-63 (1863), p. 221. 



Description. — Test free, planospiral, composed of a globular pro- 

 loculum and long, undivided tubular second chamber, coiled regu- 

 larly in one plane; wall finely arenaceous, cement yellowish or 

 reddish brown, surface smooth, aperture formed by the open end of 

 the chamber. 



As here used, Ammodiscus is restricted to include those species in 

 which the test is typically planospiral throughout. 



AMMODISCUS INCERTUS (d'Orbigny). 



Plate 39. 



Operculina incerta d'Orbigny, in De la Sagra, Hist. Fis. Pol. Nat. Cuba, 1839, 

 "Foraminif^res," p. 49, pi. 6, figs. 16, 17; Spanish Edit., 1840, p. 71, pi. 6, 

 figs. 16, 17. 



SpiriUina arenacea Williamson, Rec. Foram. Great Britain, 1858, p. 93, pi. 7, 

 fig. 203. 



Trocharnmina squamata, var. iacerla Jones and Parker, Quart. Journ. Geol. Soc, 

 vol. 16, 1860, p. 304. — Parker and Jones, Appendix to W. B. Carpenter, 

 Parker, and Jones, Intr. Foram., 1862, p. 312. 



Trocharnmina incerta W. B. Carpenter, Parker, and Jones, Intr. Foram., 

 1862, p. 141, pi. 11, fig. 2. — Haeusler, Ann. Mag. Nat. Hist., ser. 5, vol. 10, 

 1882, p. 52, pi. 3. 



Ammodiscus incerlus H. B. Brady, Rep. Voy. Challenger, Zoology, vol. 9, 1884, p. 

 330, pi. 38, figs. 1-3.— SiiERBORN and Chapman, Journ. RoyMicr. Soc, 1889, 

 p. 484, pi. 11, fig. 7. — Burrows, Sherborn, and Bailey, Journ. Roy. Micr. 

 Soc, 1890, p. 552, pi. 8, fig. 8.— J. Wright, Proc Roy. Irish Acad., vol. 1, 

 1891, p. 468.— Chapman, Journ. Roy. Micr. Soc, 1892, p. 326, pi. 6, fig. 11.— 

 Egger, Abb. bay. Akad. Wias. Miinchen, vol. 18, 1893, p. 263, pi. 5, figs. 



