550 
THE VOYAGE OF H.M.S. CHALLENGER. 
Those figured by Soldani were fossils found in the Subapennine beds of Sienna ; 
d’Orbigny’s, from the same formation, near Coroncina. 
Cristellaria cultrata, Montfort, sp. (PL LXX. figs. 4, 5, 6 ; dentate variety, figs. 7, 8). 
“Cornu Hammonis,” Plancus, 1760, Conch. Min., ed. altera, p. 120, pi. i. fig. xil, see p. 552. 
“Nautili ( Lenticiclce marginatce),” Soldani, 1789, Testaceographia, vol. i. pt. 1, p. 54, pi. xxxiii. 
figs. B, &c. 
Robulus cultratus, Montfort, 1808, Concbyl. System., vol. i. p. 214, 54 e genre. 
Robulina cultrata, d’Orbigny, 1826, Ann. Sci. Nat., vol. vii. p. 287, No. 1. — Modele No. 82. 
„ canariensis, Id. 1839, Foram. Canaries, p. 127, pi. iii. figs. 3, 4. 
,, subcultrata , Id. 1839, Foram. Amir. Merit!., p. 26, pi. v. figs. 19-20. 
„ cultrata, Id. 1846, For. Foss. Vien., p. 96, pi. iv. figs. 10—13. 
,, similis, Id. Ibid. p. 98, pi. iv. figs. 14, 15. 
'Cristellaria hoffmanni, Ehrenberg, 1854, Mikrogeologie, pi. xxvi. fig. 53. 
Robulina limbosa, Reuss, 1863, Sitzungsb. d. k. Ak. Wiss. Wien, vol. xlviii. p. 55, pi. vi. fig. 69. 
Cristellaria gyroscalprum, Stache, 1864, Novara-Exped., geol. Theil, vol. i. Palaont., p. 243, 
pi. xxiii. fig. 22, a.b. 
Robulina cultrata, var. antipodum, Id. Ibid. p. 251, pi. xxiii. fig. 30, a.b. 
„ toettovata, Id. Ibid. p. 253, pi. xxiii. fig. 32, a.b. 
Cristellaria cultrata, Parker and Jones, 1865, Phil. Trans., vol. civ. p. 344, pi. xiii. figs. 17, 18 ; 
pi. xvi. fig. 5. 
Robulina curvispira, Seguenza, 1879, Atti R. Accad. dei Lincei, ser. 3, vol. vi. p. 144, pi. xiii. 
fig. 28. 
,, stellata, Id. Ibid. p. 144, pi. xiii. fig. 29. 
„ dubia, Id. Ibid. p. 144, pi. xiii. fig. 30. 
The conspicuous feature of Cristellaria cultrata is the well-marked wing or keel 
surrounding the body of the test. The general contour of the shell is discoidal and bicon- 
vex, and the exterior is smooth and devoid of ornament. Briefly, its morphological 
characters are those of Cristellaria rotulata, with the addition of the marginal keel. 
The width of the laminar extension of the periphery varies with each individual 
specimen ; in some it occupies as much as one-third of the entire diameter of the test, 
whilst in others it is no more than a very narrow rim or border. Its outer margin is 
usually even and unbroken, but occasionally it is more or less serrate, as shown in 
figs. 7 and 8. 
The geographical distribution of Cristellaria cultrata is similar to that of the 
closely allied Cristellaria rotulata, but the area is scarcely so extensive. It has been 
found as far north as the Arctic Circle on the coast of Norway, and as far south as lat. 
50° S. on the shores of Patagonia. As a rule it affects deeper water than the non- 
carinate form, and fine specimens are rarely met with at less than 100 fathoms. The 
distribution-list comprises twelve Stations in the North Atlantic, at depths from 390 
to 2435 fathoms ; two in the South Atlantic, 350 fathoms and 675 fathoms respectively ; 
seven in the South Pacific, 38 to 275 fathoms; one in the North Pacific, 95 fathoms; and 
