FORAMINIFERA FROM THE NORTH ATLANTIC AND ARCTIC OCEANS. 
o I o 
above-mentioned ; but the exogenous growths belong to thick-shelled specimens, and 
probably indicate favourable habitats ; on the thin-shelled and the attenuate forms there 
is little or no fringing or other ornament. 
Fig. 10. Plate XV. has the chambers somewhat extended by their produced spiny 
edge or prickly fringe, and has a long apical spine ; such forms, with others (as fig. 11) 
with less of the marginal spines, occurred common and of middle size in the mixed sands 
from Norway (MacAndrew and Barrett). 
Plate XVII. figs. 70 a, 70 b, 70 c (North Atlantic). 
Figs. 70 a Sc 70 b, Plate XVII., differ somewhat one from the other and from fig. 10, 
Plate XV., in the marginal and caudal spines; but no two specimens, even among many, 
are exactly alike. 
They are common and large at 43 fathoms; common and middling at 78 and 90 
fathoms; and common and small at 223 and 415 fathoms, on the plateau off Ireland in 
the North Atlantic. 
B. marginata lives in all seas, at no great depths. 
Bulimina Presli , Eeuss, Var. acuieata , D’Orbigny. Plate XV. fig. 11 (Arctic) ; Plate 
XVII. figs. 68 & 69 (North Atlantic). 
In these specimens the chambers have a well-marked globosity, and favourable con- 
ditions of growth have given them a rapid rate of increase, as in the foregoing sub- 
variety ; the exogenous prickles, however, are less largely developed, being confined for 
the most part to the earliest chambers. 
Fig. 11, Plate XV. is an intermediate form, from Norway (mixed sands), with fewer 
marginal spines than some of its congeners ; and though more spinous than figs. 68 & 69, 
yet, as these are essentially marginatce also, and as there is a difference of degree and 
not of kind, not only among these, but between these and others presently to be described, 
it is placed under B. acuieata as its fittest place in the grouping. Its chambers have 
sharp posterior edges, drawn out into comparatively few spines, short and strong ; and 
it has a strong double caudal spine. 
B. acuieata , D’Orb., is sufficiently well figured by Soldani, Testae, vol. i. part 2, 
pi. 127. fig. 1, pi. 130. fig. vv , and pi. 131. fig. xx (the last has been unnecessarily sepa- 
rated by D’Orbigny as B. trilobata). 
Plate XVII. figs. 68 & 69 (North Atlantic). 
In figs. 68 & 69, Plate XVI. the chambers are globose, and the earliest alone are 
armed with spiny excrescences. A less developed form appears in our next variety (fig. 67). 
Figs. 68 & 69 are from the eastern marginal plateau at 223 fathoms, where B. acu- 
ieata is common and of middle size. 
B. acuieata is found everywhere with B. marginata and B. ovata. 
mdccclxv. 
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