372 
THE VOYAGE OF H.M.S. CHALLENGER. 
and not without hesitation ; hut there can no longer be any doubt that it was a needless 
addition to the nomenclature of the group. Indeed, making allowance for the geological 
age of the specimens referred to and the changes brought about by the process of mineral- 
isation, by pressure, or by other external influences to which they have been subjected, 
it is not easy to find any constant or reliable character by which they can be separated 
from the recent species. The interior of some of the fossil tests is more or less 
labyrinthic ; but this is not always the case, and the Russian specimens of the same 
form, figured by von Moller, resemble the living ones in this respect. 
Bigenerina robusta is common at Station 24, off Culebra Island, West Indies, 390 
fathoms, and at Station 122, South Atlantic, south-east of Pernambuco, 350 fathoms. 
It occurs also in one of Dr Gwyn Jeffreys’ dredgings in shallower water off Shetland. 
Bigenerina capreolus, d’Orbigny, sp. (PI. XLY. figs. 1-4). 
Vulvulina capreolus, d’Orbigny, 1826, Ann. Sci. Nat., vol. vii. p. 264, No. 1, pi. xi. figs. 5, 6 — 
Modele, No. 59. 
Schizophora neugeboreni (?) Reuss, 1861, Sitzungsb. d. k. bohm. Gesell. d. "VYiss., vol. ii. p. 16. 
Grammostomum capreolus, Parker and Jones, 1863, Ann. and Mag. Nat. Hist., ser. 3, vol. xi. p. 93. 
Textilaria flabelliformis (young stage), Giimbel, 1868, Abh. d. k. bayer. Akad. Wiss., II. Cl., vol. x. 
p. 647, pi. ii. fig. 83, a.-b. 
Venilina hceringensis, Id. Ibid. p. 649, pi. ii. fig. 84, bis., a.b. 
Schizophora hceringensis, Hantken, 1872, Mittbeil. Jabrb. d. k. ungar. geol. Anstalt., vol. i. 
p. 136, pi. ii. fig. 17, a.b. 
The test of Bigenerina capreolus is broad and compressed, and the lateral edges 
sharp and frequently more or less pectinate. The uniserial chambers are few in number, 
adult specimens very often consisting of a Textularian shell, with the addition of only 
one or two centrally -placed segments. The aperture in the early stage is Textularian ; 
in the later period terminal, and of fissurine or oval shape. 
This species was adopted by d’Orbigny as the type of his genus Vulvulina ; and 
although in the generic description it is stated that the arrangement of the segments is 
alternate throughout, the author appears to have been in some degree aware- of its 
dimorphous tendency, inasmuch as one at least of the Soldanian figures referred to 
represents a shell with two uniserial segments. The term Grammostomum 1 was 
subsequently employed by Reuss and others for the same group, more perhaps in order 
to avoid confusion between Vulvulina and Valvulina than for any better reason. 
In 1861 Reuss instituted a new genus Schizophora, which was intended to include all 
species commencing growth on the Textularian plan, and resembling Lingulina in their 
later development ; and more recently Giimbel has proposed the term Venilina for the 
1 The term Grammostomum was borrowed from Ehrenberg, but Parker and Jones have since shown, in their laborious 
analysis of the nomenclature of the various works of that author, that it was used by him indifferently for Textularix, 
Vulvulince, Bolivince, Virgulince, and Polymorpliincc. 
