FOEAMINIFERA OF THE NORTH PACIFIC OCEAN. 



U 



In its general simple structure this genus is analogous to Cornu- 

 spira among the imperforate calcareous forms and to Ammodiscus 

 among the arenaceous forms. By some authors these have been 

 classed together but it seems merely a case of parallelism as is found 

 among so many of the various groups of the Foraminifera. 



SPIRILLINA VIVIPARA Ehrenberg. 

 Plate 1, figs. 1, 2. 



Spirillina vivipara Ehrenberg, Abh. Akad. Wiss. Berlin, 1841, p. 442, pi. 3, 



fig. 41. — Williamson, Mem. and Proc. Manchester Lit. and Philos. Soc, 



ser. 2, vol. 8, 1848, p. 45, pi., fig. 34. — Parker and Jones, Ann. Mag. Nat. 



Hist., ser. 2, vol. 19, 1857, p. 284, pi. 11, fig. 46; Philos. Trans., vol. 155, 



1865, p. 397, pi. 15, fig. 28. — Moebius, Beitr. Meeresfauna Insel Mauritius, 



1880, p. 88, pi. 8, figs. 1, 2.— Goes, Kongl. 



Svensk.Vet. Akad. Handl., vol.19, 1882, p. jSC^V Q 



108, pi. 7, fig. 272— H. B. Brady, Rep. Voy. 



Cliallenger, Zoology, vol. 9, 1884, p. 630, pi. 



85, figs. 1-5. — Balkwill and Wright, Trans. 



Roy. Irish Acad., vol. 28 (Sci.) 1885, p. 348, 



pi. 12, fig. 32. — BtJTSCHLi, Morph. Jahrb., 



vol. 11, 1886, p. 84, pi. 6, fig. 12— Egger, 



Abh. kon. bay. Akad. Wiss. Munchen, Cl. n, 



vol. 18, 1893, p. 394, pi. 18, figs. 56-58; vol. 21, a b 



1899, p. 18, pi. 1, figs. 50, 51. — Flint, Rep. Fig. 1.— Spirillina vivipara Ehren- 



U. S. Nat. Mus., 1897 (1899), p. 326, pi. 71, berg, x 100. a, front view; b, 



fig. 4.-MLLLETT, Journ. Roy. Micr. Soc, ™™ ALVIEW " (ADAPTED FR0M 



1903, p. 693.— Rhumbler, Zool. Jahrb., 



Abth. Syst., vol. 24, 1906, p. 32, pi. 2, fig. 7.— Chapman, Journ. Quekett 



Micr. Club, ser. 2, vol. 10, 1907, p. 133. — Sidebottom, Mem. and Proc. 



Manchester Lit. and Philos. Soc, vol. 52, No. 13, 1908, p. 6, pi. 1, figs. 12-14; 



pi. 2, figs. 1-3; vol. 54, No. 16, 1910, p. 24. 

 Operculina punctata Reuss, Denkschr. Akad. Wiss. Wien, vol. 1, 1849, p. 370, 



pi. 46, fig. 21. 

 Cornuspira perforata Schultze, Organ. Polythal., 1854, p. 41, pi. 2, fig. 22. 

 Spirillina perforata Williamson, Rec Foram. Great Britain, 1858, p. 92, pi. 7, 



fig. 202. 



Description. — Test typically free, rarely adherent, planospiral, 

 coils of early portion in microspheric specimens at least narrow, 

 those of later coils much wider and of nearly uniform width, faces 

 sometimes flattened but more often concave on both sides; sutures 

 usually distinct and often considerably depressed; peripheral border 

 rounded; wall marked by conspicuous perforations, irregularly scat- 

 tered and most prominent on the last formed volutions; aperture 

 somewhat crescentic. 



Diameter 0.4-0.75 mm. 



Distribution. — Brady records the occurrence of this species in the 

 North Pacific without definite station. Rhumbler records it both 

 from Laysan and the Chatham Islands. I have found the species 

 but a few times in the material at my disposal, largely due, I sup- 

 pose, to the fact that it was with few exceptions from fairly deep 



