FORAMINIFERA FROM THE NORTH ATLANTIC AND ARCTIC OCEANS. 401 
Both the feeble (Nonionine) and the well-grown varieties of Polystomella are distri- 
buted very widely, but avoid great depths. The thick-shelled P. craticulata is found in 
tropical seas ; the medium-conditioned P. crispa is extensively spread about in temperate 
seas ; P. Arctica and P. striatopunctata are the best of the species found in cold seas. 
The Nonionince accompany their better-grown congeners ; N. asterizans and N. depres- 
sula affecting temperate climates ; N. Scaplia and N. umbilicatula being found more often 
in the warmer seas. 
Polystomella crispa stands midway between those Nonionince that begin to take on a 
barred aperture and perforated septal furrows, and those that have cribriform septa and 
a surface masked with septal bridges and other exogenous shell-matter ; it is therefore 
a good type, showing the generic and specific characters without exaggeration. It has 
been well illustrated and described by Williamson, Carpenter, and Schultze; and its 
many modifications, in the recent and fossil state, have received as many names. In 
some Tertiary beds P. crispa is plentiful ; and it abounds at the present day in temperate 
and warm seas. 
We find P. crispa in the dredgings from the Hunde Islands (at 25 to 30 fathoms) rare 
and small; and very rare and small in the North Atlantic at 725 fathoms, north of the 
Newfoundland Bank. 
Polystomella crispa , Linn., sp., Var. Arctica , nov. Plate XIV. figs. 25-30 (Arctic). 
One of the varietal stages presented by the simpler Polystomellce is characterized by 
double pores for the canals in lines along the septal furrows of the shell, an advance 
upon the simple single pores of P. striatopunctata , and an approach to the higher 
Polystomellce. These double-pored furrows belong to a rounded, bun-like, Nonionine 
shell, with barred aperture, sparsely perforated septa, and a tendency to irregularity of 
growth ; the neat, definite, lenticular, sharp-edged, discoidal shell of Polystomella proper 
being but poorly represented as yet. The essential characters, however, of pores in the 
furrows and septal apertures are not to be mistaken, although the retral processes of the 
chambers and the intervening fossettes are very rudimentary. The spiral lamina is 
finely perforate. 
This form differing from the smaller P. striatopunctata , Fichtel and Moll, sp., in 
having double pores for its lateral canals, shows thus much a differentiation of the shell- 
structure in relation to the forking tubes, which are single in P. striatopunctata (figs. 
31-34). With this exception, and with some additional apertures, P. Arctica keeps to 
the simple type ; but it attains a semigigantic size, having a similar relation to P. stria- 
topunctata that P. craticulata has to P. crispa. 
One individual (fig. 27) shows a tendency to produce rough exogenous accumulations 
of shell-substance, as is the habit of P. craticulata. 
P. Arctica is peculiar to the most northern seas, and occurs plentifully at the Hunde 
Islands at from 30 to 40 and 60 to 70 fathoms (Sutherland) in company with P. striato- 
punctata. Mr. H. B. Brady has found it in Mr. Jeffreys’s dredgings made at Shetland, 
in some abundance, and of a brown colour. 
