FORAMINIFERA OF THE NORTH PACIFIC OCEAN. 23 



The higher genera of this family have been made the objects of 

 critical researches by many writers and students of the Foraminifera, 

 and their structure, although often complicated, is well known and 

 abundantly illustrated. 



Genus NONIONINA d'Orbigny, 1826. 



Nautilus (part) Walker and Jacob, Adam's Essays, Kanmacher's Ed., 1798, 



p. 641. 

 Polystomella (part) DeFrance, Diet. Sci. Nat., vol. 32, 1824, p. 183. — Parker 



and Jones, Philos. Trans., vol. 155, 1865, p. 403. 

 Nonionina d'Orbigny (type, N. umbilieatula d'Orbigny=iV. pompilioides (Fich- 



tel and Moll)), Ann. Sci. Nat., vol. 7, 1826, p. 293.— H. B. Brady, Rep. Voy. 



Challenger, Zoology, vol. 9, 1884, p. 724. 



Description. — Test composed of numerous chambers arranged to 

 form a bilateral, nautiloid coil, the last formed volution usually 

 embracing all the preceding ones; walls usually smooth, sometimes 

 pitted, very finely perforated; aperture a narrow opening or row of 

 openings at the base of the apertural face, between it and the pre- 

 ceding volution. 



In Nonionina the skeleton of the test is simple with little trace of 

 the supplementary test being developed. The aperture is usually 

 simple but in some species shows a tendency to become a series of 

 openings as in some of the higher forms. Usually the last formed coil 

 completely embraces the previously formed ones, but the test may be 

 umbilicate, exposing the earlier coils at the umbilicus. In some 

 species there is a tendency more or less marked to form a star-shaped 

 thickening at the umbilical region, extending outward along the 

 sutures between the chambers. 



NONIONINA DEPRESSULA (Walker and Jacob). 

 Plate 17, fig. 3. 



"Nautilus spiralis utrinque subumbilicatus " Walker and Boys, Test. Min., 

 1784, p. 19, pi. 3, fig. 68. 



Nautilus depressulus Walker and Jacob, Adam's Essays, Kanmacher's Ed., 

 1798, p. 641, pi. 14, fig. 33. 



Nonionina depressula Parker and Jones, Ann. Mag. Nat. Hist., ser. 3, vol. 4, 

 1859, pp. 339, 341.— H.B.Brady, Rep. Voy. Challenger, Zoology, vol. 9, 1884, 

 p. 725, pi. 109, figs. 6, 7. — H. B. Brady, Parker, and Jones, Trans. Zool. 

 Soc, vol. 12, 1888, p. 229, pi. 43, fig. 25.— Egger, Abh. kon. bay. Akad. 

 Wiss. Munchen, CI. n, vol. 18, 1893, p. 427, pi. 19, figs. 38, 39.— Goes, Kongl. 

 Svensk. Vet. Akad. Handl., vol. 25, 1894, p. 103, pi. 17, figs. 825, 826.— 

 Morton, Proc. Portland Soc. Nat. Hist., vol. 2, 1897, p. 121, pi. 1, fig. 20.— 

 Wright, Geol. Mag., dec. 4, vol. 7, 1900, p. 100, pi. 5, fig. 23.— Fornasini, 

 Mem. Accad. Sci. 1st. Bologna, ser. 6, vol. 1, 1904, p. 12, pi. 3, fig. 6 — 

 Millett, Journ. Roy. Micr. Soc, 1904, p. 599. — Bagg, Proc. U. S. Nat. Mus., 

 vol. 34, 1908, p. 164.— Sidebottom, Mem. and Proc. Manchester Lit. and 

 Philos. Soc., vol. 53, No. 21, 1909, p. 12, pi. 4, fig. 8; vol. 54, No. 16, 1910, 

 p. 29.— Bagg, Bull. U. S. Geol. Surv., No. 513, 1912, p. 88, pi. 26, figs. 16a-<y 

 pi. 28, figs. 7, 8. 



