FORAMINIFERA FROM THE NORTH ATLANTIC AND ARCTIC OCEANS. 405 
The specimens from Newfoundland Bank are rare and have a deadish look, as if 
drifted from their more favourable northern habitats. 
Polystomella crispa, Linn., sp., Var. ( Nonionina ) umbilicatula , Montagu, sp. Plate XIV. 
figs. 42 a, 42 b (Arctic); Plate XVII. figs. 58, 59 (North Atlantic). 
This is a small, neat, many-chambered, Nautiloid Nonionina , with hollow umbilici. 
See Ann. Nat. Hist. 3rd ser. vol. iv. pp. 346 & 347, and vol. v. p. 101, &c., for a com- 
parison of this and other Nonionince. It is common at greater depths than most other 
Nonionince, except N. Scapha , affect ; it is found in warm seas, and occurs in many 
Tertiary deposits. 
We have it in the mixed sands from the Norway coast (MacAndrew and Barrett). 
In the North Atlantic N. umbilicatula is common and of middle-size on the marginal 
plateau off Ireland, at 78, 90, 223, and 415 fathoms; in the abyssal depths it is rare and 
small at 1776, rather common and middle-sized at 1950, rather common and small at 
2050 and 2176 fathoms; and at 2350 fathoms in the “ Boreal” part of the abyss it is 
rare and small : north of Newfoundland Bank, at 329 fathoms, and in Trinity Bay at 
150 fathoms, it is very rare and small; cold water having as bad an influence on it as 
abyssal depth. 
This form, being flush-celled, is more thoroughly changed in character from the type 
than the feeble varieties found in shallow water, such as P. stelligera and P. depressula. 
In these the vesicularity of the chambers allows of the formation of some rudiments of 
the retral processes, the overlying bridges, and the intervening fossettes ; but in this 
deeper-sea variety the septal walls of contiguous chambers become perfectly adapted, 
and their edges grow close together at the surface of the shell. This is well shown in 
the recent and fossil specimens of this kind from the Mediterranean area ; further north, 
however, it scarcely holds its own, and intermediate forms are always turning up, which 
connect this with the vesicular varieties. 
Polystomella crispa, Linn., sp., Var. ( Nonionina ) turgida, Williamson, sp. Plate XVII. 
figs. 57 a , 57 b , 57 c (North Alantic). 
A delicate ovate Nonionina ; the chambers increasing so rapidly in size that the dis- 
coidal form is lost, and we have the shape of the Argonauta instead of the Nautilus. 
The latter chambers, too, in adult specimens are apt to be swollen at the umbilical 
margin, concealing the spiral parts of the shell, and hanging over a little more on one 
side than the other. 
Our figured specimen is much thicker and more symmetrical than Professor William- 
son’s Botalina turgida (Monogr. p. 50, pi. 4. figs. 95-97), but they both belong to the 
same variety. 
N. turgida is found in shallow and brackish water in the British area ; and occurs 
especially in the sub-recent clay of Peterborough Fen, rather common, but extremely 
small, starved, and one-sided. 
mdccclxv. 3 i 
