FORAMINIFERA FROM THE NORTH ATLANTIC AND ARCTIC OCEANS. 409 
Miliola ( Spiroloculina ) limbata, D’Orbigny. Plate XVII. figs. 83 a, 83 b (North Atlantic). 
Here the edges of the chambers are limbate, or thickened with shell-growth, a non- 
essential feature. It is figured by Soldani and named by D’Orbigny, Ann. Sci. Nat. 
vol. vii. p. 299, No. 12. 
We have Spiroloculina limbata rare and small from the Irish marginal plateau of the 
North Atlantic, at 78 fathoms. It is not rare in the existing seas, and occurs in the 
Tertiary deposits. 
Miliola ( Biloculina ) ringens, Lamarck. Plate XV. figs. 42-44 (Arctic). 
Taking the Biloculine Miliolce by themselves, this well-known common Biloculina 
ringens , Lamarck, is the type of a very variable group. Not only the degree of globo- 
sity of the chambers, but the amount of overlap at the sides or at the ends, constitute 
infinite variations, presented in all seas. 
Large Biloculina, but subject to great differences in the points above alluded to, were 
found abundantly in nearly all the dredgings from Norway. Fig. 44 represents a highly 
globose and striated specimen from Norway. Dr. Wallich figures B. ringens in ‘ The 
North- Atlantic Sea-bed,’ pi. 5. figs. 1, 3, 4, 6. 
Miliola ( Biloculina ) depressa, D’Orbigny. Plate XVII. figs. 89 a, 89 5 (North Atlantic). 
This depressed form of Biloculina ringens is not uncommon in both the recent and 
fossil (Tertiary) states. D’Orbigny illustrated it by his Modele, No. 91. 
It occurs in several soundings from the North Atlantic, though rare in each. It is 
small on the Irish plateau at 43 and 78 fathoms; small at 2176 fathoms, and middle- 
sized at 1450, 1660, and 2350 fathoms in the abyss. It is figured in Dr. Wallich’s 
‘ North- Atlantic Sea-bed,’ pi. 5. figs. 2, 5, 8. 
Miliola ( Biloculina ) elongata, D’Orbigny. Plate XVII. figs. 88, 90, 91 (North Atlantic). 
Biloculina ringens contracted gives B. elongata , figured by Soldani and named by 
D’Orbigny, Ann. Sci. Nat. vol. vii. p. 298, No. 4, and not rare wherever other Bilocu- 
lince exist. 
We have B. elongata from the North Atlantic, small and rare in the deep, at 1950, 
2050, and 2330 fathoms. 
Miliola ( Triloculina ) tricarinata, D’Orbigny. Plate XV. fig. 40 (Arctic). 
Triloculina tricarinata , D’Orb. (Modeles, No. 94) differs from Tr. trigonula, Lamarck, 
in having produced or keeled edges. Our figured specimen has rather flatter sides than 
are usual. 
Tr. tricarinata , D’Orb., has a very wide distribution and, like T. trigonula , Lam., 
abounds in some Tertiary beds. The sea-sand near Melbourne, Australia, yields large 
specimens of Tr. tricarinata , together with striped Tr. trigonula. At the Hunde 
Islands Tr. tricarinata is small, common at 25 to 30 fathoms, rare at 60 to 70 fathoms. 
