616 
THE VOYAGE OF H.M.S. CHALLENGER. 
Pullenia sphceroides, Carpenter, 1862, Introd. Foram., p. 184, pi. xii. fig. 12. 
,, „ Parker and Jones, 1865, Phil. Trans., vol. civ. p. 368, pi. xiv. figs. 43, a.b. 
„ bulloides, Eeuss, 1866, Denkschr. d. k. Akad. Wiss. Wien, vol. xxv. p. 150. 
„ sphceroides, Terrigi, 1880, Atti dell’ Accad. Pontif., ann. xxxiii. p. 189, pi. L fig. 21. 
Fig. 18. — Pullenia sphce- 
roides. Horizontal sec- 
tion, showing the arrange- 
ment of the chambers. 
Magnified 100 diameters. 
In general external appearance Pullenia sphceroides bears a close resemblance to the 
thicker varieties of the genus Nonionina. It is a minute species, perhaps the smallest 
of all the Globigerinidce, the diameter of the adult test ranging 
from i-J-oth to -^g-th inch (0T7 mm. to 0-34 mm.). The shell is 
subglobular, usually somewhat compressed in the direction of 
the axis ; and it is composed of from three to four convolutions, 
each of which consists normally of four segments. The segments 
are much arched and extend from pole to pole, so that each 
convolution completely invests those previously formed. The 
septal face is extremely narrow ; and the aperture is a crescenti- 
form slit, almost the entire length of the final segment, inserted at 
its inner margin, close to the line of union with the preceding 
convolution. The surface of the shell is smooth, and the sutures are marked externally by 
fine lines with little or no superficial depression. The walls are very finely perforated ; 
and, judging from the appearance of transverse sections of the shell, the diameter of 
the pore-canals does not exceed inch (0*001 mm.). 
Pullenia sphceroides is a nearly cosmopolitan species. Its area of distribution 
reaches fromlat. 70° N., or thereabouts, to lat. 54° S.; and its bathymetric range extends 
from the laminarian zone down to 2750 fathoms, but it is comparatively rare at depths of 
less than 300 fathoms. The list of localities includes Davis Strait and the shores of 
Novaya Zemlya, the east coast of Norway, the Faroe Channel, the British seas, the 
Mediterranean, and the Red Sea : its occurrence has been noted at no less than twenty- 
two Stations in the North Atlantic, six in the South Atlantic, four in the Southern 
Ocean, fifteen in the South Pacific, and five in the North Pacific. 
From a geological point of view, Pullenia sphceroides is first conspicuous as a 
Cretaceous Foraminifer. It presents itself in the Chalk of Westphalia (Reuss) and of the 
Island of Rugen (Marsson), and in the Chalk-marl of Lemberg (Reuss). It is found in 
the Eocene clay of the London Basin (Jones and Parker), and in the Septaria-clays of 
various parts of Germany (Reuss, Bornemann) ; in the Miocene deposits of Vienna 
(d’Orbigny, Reuss, Karrer), of the Banat (Karrer), and of Malta (Brady), and in the 
Salzthon of Wieliczka (Reuss). It occurs also in the Subapennine formations of Italy 
(d’Orbigny, Costa, &c.), in the Vatican Sands (Terrigi), and in the Crag of Norfolk and 
Suffolk (Jones, Parker, and Brady). 
