706 
THE VOYAGE OF H.M.S. CHALLENGER. 
A few specimens with these characters not quite so strongly marked as indicated by 
Karrer’s figure, were dredged off Ki Islands, 580 fathoms. 
Rotalia orbicularis, cf'Orbigny (PI. CVII. fig. 5 ; PL CXV. fig 6). 
Rotalia ( Gyroidina ) orbicularis, d’Orbigny, 1826, Ann. Sci. Nat., vol. vii. p. 278, No. 1 • — 
Modele, No. 13. 
Rotalia orbicularis, Brady, 1864, Trans. Linn. Soc. Lond., vol. xxiv. p. 470, pi. xlviii. fig. 16. 
„ beccarii, var. orbicularis, Parker and Jones, 1865, Phil. Trans., vol. civ. p. 389, pi. xvi. 
fig. 34. 
Rotalia orbicularis, Terquern, 1882, Mbm. Soc. g4ol. France, s6r. 3, vol. ii., Mem. III., p. 60, 
pi. iv. figs. 1-3. 
The test of Rotalia orbicularis is approximately plano-convex, the superior face being 
flat or only slightly arched, the inferior convex and more or less excavated at the 
umbilicus, and the peripheral edge subangular. It is isomorphous with Truncatulina 
lobatula in the Planorbuline series, and forms a connecting link between Rotalia beccarii 
and Rotalia soldanii. 
The species is very widely diffused. It has been found over considerable areas of the 
North and South Atlantic, the Mediterranean, the Red Sea, the Southern Ocean, and the 
North and South Pacific, the record extending in all to nearly forty localities. Its 
northern limit appears to be about lat. 60° N., in the Atlantic ; its southern boundary 
about lat. 43° S., in the Southern Ocean. Its bathymetrical range extends from 100 
fathoms to 2400 fathoms, but it is most at home at moderate depths. 
Fossil specimens have been found in the London Clay (Jones and Parker) and in the 
Eocene formations near Paris (d’Orbigny, Terquern) ; in the Miocene of Southern Italy 
(Seguenza), and in the later Tertiaries of Italy and of the south-east of Spain (Jones 
and Parker) ; in the Crag of Antwerp (Reuss), and of Suffolk (Jones, Parker, and Brady), 
and in the Post-tertiary deposits of Norway (Crosskey and Robertson). 
Rotalia soldanii, d’Orbigny (PI. CVII. figs. 6, 7). 
Rotalia {Gyroidina) soldanii, d’Orbigny, 1826, Ann. Sci. Nat., vol. vii. p. 278, No. 5; — Modele, 
No. 36. 
Rotalia girardana, Reuss, 1851, Zeitscbr. d. deutsch. geol. Gesellsch., vol. iii. p. 73, pi. iii. fig. 34. 
,, beccarii, var. soldanii, Parker and Jones, 1865, Phil. Trans., vol. civ. p. 389, pi. xvi. 
figs. 31-33. 
,, nitidula, Schwager, 1866, Novara-Exped., geol. Theil, vol. ii. p. 263, pi. vii. fig. 110. 
,, soldanii, Hantken, 1875, Mittheil. Jahrb. d. k. nng. geol. Anstalt., p. 80, pi. ix. 
fig. 7, a.b.c. 
The plano-convex habit of growth reaches its extreme development, so far as the 
present genus is concerned, in Rotalia soldanii, the test of which resembles that of 
Rotcdia orbicularis, except that the convexity of the inferior or umbilical side is 
