REPORT ON THE FORAMINIFERA. 
735 
subcarinate and the umbilici turgid or slightly umbonate ; the septa are more or 
less depressed, and the septal bridges and fossettes present exactly the same aspect as 
those of Polystomella striatopunctata. 
As a living Foraminifer Polystomella sub nodosa has only been identified at two 
points, amongst the islands south-west of Papua, namely: — Station 187, off Booby Island, 
depth 6 to 8 fathoms; and Station 188, depth 28 fathoms. 
Fossil specimens occur in the Septaria-clay and the Upper and Lower Oligocene forma- 
tions of various parts of Germany (Munster, Boll, Reuss) and in the Upper Pliocene of 
the Island of Rhodes (Terquem). 
Polystomella arctica , Parker and Jones (PL CX. figs. 2-5). 
Polystomella arctica (P. & J., MS.), Brady, 1864, Trans. Linn. Soc. Lond., vol. xxiv. p. 471, 
pi. xlviii. fig. 18. 
,, crispa, var. arctica , Parker and Jones, 1865, Phil. Trans., vol. civ. p. 401, pi. xiv. 
figs. 25-30. 
,, arctica, Brady, 1878, Ann. and Mag. Nat. Hist., ser. 5, vol. i. p. 437, pi. xxi. 
fig. 13, a.d. 
The general contour of Polystomella arctica is similar to that of Polystomella 
striatopunctata, though the specimens of the former attain much larger dimensions. 
Typically the shell is discoidal, with nearly flat lateral faces and rounded periphery ; 
the retral processes of the segments are abortive, and consequently there are no septal 
bridges ; the sutures are nearly complanate externally, and are marked by a double row 
of pores, the openings of a partially developed system of interseptal canals, the two rows 
being often separated by a raised band of shell-substance. The walls of the test are 
generally much thickened, and present a laminated appearance when seen in section 
(fig. 4). The aperture is a crescentiform fissure more or less subdivided by clenticulations 
of the superior edge. There are also frequent indications of a second row of orifices, 
parallel to the normal aperture, a little higher up on the septal face (fig. 5). The test 
attains a diameter of ^th inch ( L '26 mm.) or more. 
Polystomella arctica is exclusively a boreal and almost exclusively an arctic species. 
It is common in Baffin’s Bay and Smith Sound, as far north as lat. 82° 27' N., at every 
depth down to 210 fathoms ; off the Huncle Islands, Davis Strait, 25 to 70 fathoms ; on 
the shores of Spitsbergen, 7 fathoms; off Franz- Joseph Land, lat. 79° to 80° N., 108 to 
125 fathoms ; and off Novaya Zemlya, 55 to 93 fathoms. It is comparatively rare in the 
Faroe Channel and the Shetland Seas ; and its southern limit, so far as at present 
known, is reached on the western coast of Scotland. 
Mr. Wright has met with specimens in the Boulder-clay of the north-east of Ireland, 
but it has not been found elsewhere in the fossil state. 
