FORAMINIFERA FROM THE NORTH ATLANTIC AND ARCTIC OCEANS. 
377 
Genus Cassidulina. 
Cassidulina Icevigata , D’Orbigny. Plate XV. figs. 1-4 (Arctic); Plate XVII. figs. 64 a, 
64 b , 64 c (North Atlantic). 
Cassidulina , related to Bulimina and Textularia , is described in Carpenter’s Introd. 
Poram. p. 197. It is of world-wide distribution, on muddy bottoms in both shallow and 
deep waters. In the Indian Ocean (between Socotra and Kurachee) Cassidulina takes 
on the uncoiled condition (Cassidulina Pupa, D’Orb., Ehrenbergina serrata , Eeuss) ; and 
in the tropical deep seas it passes into thick-walled, flush-shelled, and uncoiled forms, 
isomorphic of Bolivince. It occurs in Tertiary deposits. Deep-sea forms are usually 
thick-walled. 
C. Icevigata , D’Orb. (Modeles, No. 41, Ann. Sc. Nat. vii. p. 282, pi. 15. figs. 4, 5 bis) 
is common and small in the mixed sands from Norway (MacAndrew and Barrett) ; 
common and middle-sized at the Hunde Islands, from 30 to 70 fathoms*; common and 
middle-sized in 150 fathoms, 76° 30' lat., 77° 52' long., Baffin’s Bay, and rare and middling 
at 75° 10' lat., 60° 12' long. 
In the North Atlantic it is rare and small at 1750 fathoms in the central area ; north 
of the Bank it is rare and of middle size at 102, 112, and 145 fathoms, and rather 
common at 740 fathoms ; in Trinity Bay it is rare and small at 150 fathoms, middle-sized 
and not very common at 124, 133, and 192 fathoms. 
On the Newfoundland Bank Cassidulince are few and probably dead, just as Nonio- 
nina S capita occurs. Cassidulina is also a Middle Tertiary form. 
Cassidulina Icevigata , D’Orb., Var. crcissa, D’Orb. Plate XV. figs. 5, 6, 7 (Arctic); 
Plate XVII. fig. 64 d (North Atlantic). 
This thicker form accompanies the typical C. laevigata in its wide-spread occurrences. 
D’Ordigny first described and figured C. crassa from off Cape Horn (160 metres), and, in 
company with C. Pupa, from the Falkland Isles (“at a considerable depth”). Professor 
Williamson’s C. obtusa (Monogr. p. 69, pi. 6. figs. 143, 144), from the British coasts, 
and from the Hunde Islands, is the same as C. crassct , excepting a slight difference in 
the variable aperture. 
C. crassa , D’Orb. (For. Amer. Mer. p. 56, pi. 7. figs. 18—20) is small at 28-30 and 
50-70 fathoms, and of middle size at 30-40 fathoms at the Hunde Islands, and common 
throughout ; it is common and small at 150 fathoms in Baffin’s Bay, 76° 30' lat., 77° 52' long. 
On the eastern plateau of the North Atlantic it is very rare and very small at 223 
fathoms. 
C. crassa has its finest development (as far as we know) at 1100 fathoms in the Tro- 
pical Atlantic ; like C. laevigata it is often among the deep-sea forms ; it is found also in 
the Mediterranean and in Bombay Harbour. 
* Professor Williamson (Monogr. p. 68) notices the nmhonate and transparent condition of the Cassidulince 
from the Hunde and Beechey Islands. 
