REPORT ON THE FORAMINIEERA. 
145 
Una elongata of tlie Tableau Methodique is tbe same in all essential features as the 
Biloculina bougainvillei and Biloculina patagonica of tlie “ South America ” memoir, 
scarcely admits of a doubt. The segments vary a good deal in form in different speci- 
mens, and it is seldom they are quite so regular and symmetrical as in that figured in 
PL II. fig. 9. 
Biloculina elongata is cosmopolitan. It is common in the littoral and shallow- water 
sands of our own shores and throughout the temperate zones, but seeks somewhat deeper 
water in the tropics. Judging from the Challenger gatherings, it appears to be more 
abundant in the North Atlantic and South Pacific than elsewhere. 
Biloculina depressa, cVOrbigny (PI. II. figs. 12, 15-17; PI. III. figs. 1, 2). 
“Frumentaria Lenticidce,” Soldani, 1795, Testaceograpkia, vol. i., part 3, p. 231, pi. civ. 
figs, yy , zz. 
Biloculina depressa, d’Orbigny, 1826, Ann. Sci. Nat., vol. vii. p. 298, No. 7 ; — Modele, No. 91. 
„ carinata, Id., 1839, Foram. Cuba, p. 148, pi. viii. fig. 24 ; pi. ix. figs. 1, 2. 
,, lunula, Id., 1846, For. Foss. Vien., p. 264, pi. xv. figs. 22-24. 
„ ampliicouica, Reuss, 1850, Denkschr. d. k. Ak. Wiss. Wien, vol. i. p. 382, pi. xlix. 
fig. 5. 
„ ringens, var. carinata, Williamson, 1858, Rec. For. Gt. Br., p. 79, pi. vii. 
figs. 172-174. 
Miliola ( Biloculina ) depressa, Parker and Jones, 1865, Phil. Trans., vol. civ. p. 409, pL xvii. 
fig. 89, a, b. 
Biloculina depressa, Jones, Parker and Brady, 1866, Foram. Crag., p. 6, pi. iii. figs. 29, 30. 
As may be inferred from what has been already stated, the only distinctive features of 
Biloculina depressa are the compressed contour, and the thin, angular, peripheral margin. 
The degree of compression varies greatly, and the thicker specimens furnish the connect- 
ing links between the present species and the typical Biloculina ringens. In like 
manner the aperture presents every gradation of form from the nearly round, somewhat 
tubular mouth, represented in PI. II. fig. 15, to the broader orifice of figs. 12 and 16, and 
even to the linear slit shown in PI. III. figs. 1, 2. In rare instances when the aperture 
takes the long, slit-like character, the superior lip projects somewhat beyond the normal 
periphery of the shell ; and on the production of a fresh segment this projection is not 
enclosed with the rest of the margin, but remains as a sort of appendage to the inferior 
extremity, and gives rise to such modifications as figs. 1, 2 just referred to, or as the speci- 
men figured by Karr er (Geol. d. K. F.-J. Wasserleitung, pi. xvi. a, fig. 7). This peculiarity 
is not confined to the compressed varieties, but is also met with in the stouter species. 
The distribution of Biloculina depressa is coextensive with that of the type, both 
from a geographical and geological point of view. It must, however, be mentioned that 
Terquem and Berthelin figure under the name Biloculina liassina (Mem. Soc. geol. 
France, ser. 2, vol. x. p. 77, pi. xvi. fig. 7) specimens obtained from the Middle Lias of 
Essey-lks-Nancy, which appear to me indistinguishable from the present species except 
