FORAMINIFERA OF NORTH PACIFIC OCEAN. 73 



Subfamily 4. AMMOD1SCINJE. 



Test composed of a globular proloculum and long undivided tube, 

 closely coiled, either planospirally or in changing planes or to form 

 a spiral test; wall of fine sand with much cement. 



Ammodiscus and its allies Gordiammina, Ammodiscoides, and 

 Turritellella form a rather unified group in that they are all close coiled 

 and are of fine material, with an abundance of reddish cement. As 

 far as known the tests are all free. In Ammodiscus the two forms, 

 microspheric and megalospheric, are known to occur. 



Genus AMMODISCUS Reuss, 1861. 



Operculina (part) d'Orbigny, Foram. Cuba, 1839, p. 71. 



Orbis Strickland, Quart. Journ. Geol. Soc, vol. 2, 1846, p. 30 (not Orbis of Phil- 

 ippi, 1844= Cornuspira). 



Spirillina Williamson, Recent Foraminifera of Great Britain, 1858, p. 93 (not 

 Spirillina Ehrenberg, 1841). 



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

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

 p. 141. 



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

 p. 365. — Butschli, in Bronns Klassen und Ordnungen den Thierreieh^, 

 vol. 1, 1880, p. 189.— H. B. Brady, Rep. Voy. Challenger, Zoology, vol. 9, 

 1884, p. 329.— Rhumbler, Nachr. kon. Ges. Wise. Gottingen, 1895, p. 84.— 

 Eimer and Fickert, Zeitschr. wiss. Zool., vol. 65, 1899, p. 614.— Rhum- 

 bler, Arch. Protistk., vol. 3, 1903, p. 280. (Type, A. incertus d'Orbigny 

 =Operculina incerta d'Orbigny). 



Cornuspira (part) Reuss, and various authors (not Cornuspira Schultze, 1854). 



Involutina (part) Terquem, Mem. Acad. Imp. Metz, 1S60-61 (1862), p. 450; 

 1862-63 (1863), p. 221. 



Description. — Test free, spiral, composed of a proloculum and 

 long undivided tubular second chamber, coiled regularly in one 

 plane, wall finely arenaceous, cement usually brown, surface smooth. 



I have restricted Ammodiscus to the basis of Rhumbler, including 

 only those species which have a truly planospiral test. 



AMMODISCUS INCERTUS (d'Orbigny). 



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

 "Foraminiferes," p. 49, pi. 6, figs. 16, 17; Spanish Edit., 1840, p. 71, pi. 6, 

 figs. 16, 17. 



Spirillina arenacea Williamson, Recent Foraminifera of Great Britain, 1858, 

 p. 93, pi. 7, fig. 203. 



Trochammina squamata, var. incerta Jones and Parker, Quart. Journ. Geol. 

 Soc, vol. 16, 1860, p. 304. — Parker and Jones, Appendix to W. B. Car- 

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



Trochammina incerta W. B. Carpenter, Parker, and Jones, Intr. Study Foram., 

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

 10, 1882, p. 52, pi. 3. 



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

 p. 330, pi. 38, figs. 1-3. — Sherborn and Chapman, Journ. Roy. Micr. 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., 



