400 Mr. H. B. Brady on some Arctic Foraminifera. 
addition three arenaceous species with the same very general 
distribution—Reophax difflugiformis, Reophax scorpiurus, and 
Haplophragmium nanum. ‘These forms, so far as is known, 
are very rare or entirely absent in corresponding latitudes on 
the western or American side of the Arctic Ocean. 
Comparing the set of soundings in the Novaya-Zemlya 
sea (A—-F) with those from Franz-Josef Land (G—P) it may 
be noticed that one or two species, such as Nonionina scapha, 
which are abundant in the former, are absent, or nearly so, 
from the latter series; and the genus Lagena, though still 
represented by a few specimens, diminishes in frequency as 
we proceed northwards. On the other hand, Saccammina 
spherica, which is the most prominent Foraminifer on the 
shores of Franz-Josef Land, has not been found in any of the 
southern group of soundings ; and the other arenaceous species 
are also conspicuous by their size and abundance in the more 
northern region. 
The influence of climate and other external conditions 
in modifying morphological characters is a subject full of 
interest, though it is much more easy to observe the changes 
that take place than to account satisfactorily for them. 
Some of the coarse arenaceous types, such as Saccammina 
spherica and, in deeper water, Rhabdammina abyssorum, 
attain their maximum size and importance in the polar 
seas; whilst upon other sandy forms the more northerly con- 
ditions appear to have a starving or depauperating effect. 
For example, Haplophragmium globigeriniforme, which in 
the North Atlantic is often 1:6 millim. in diameter, is re- 
presented in the soundings from Franz-Josef Land by speci- 
mens not much more than one tenth of that size (0:18 
millim.). Globigerina bulloides, of which the North-Atlantic 
specimens are often 0-6 millim. or more in diameter, and have 
the typical subglobular segments, is represented in the arctic 
area by a thick-shelled variety, with a diameter of about 0°3 
millim. and much more compactly built. 
There is another peculiarity, common amongst northern 
specimens of certain clear-shelled perforate species, that I do 
not think has been previously noticed, namely the habit of 
covering the shell with a coat of very fine loose sand. This 
may be seen in the genera Nonionina and Polystomella, and in 
adherent specimens of TZruncatulina lobatula. The latter 
species, in its young parasitic condition, frequently constructs 
a perfect nédus, in the form of a convex tent-like covering of 
light-coloured sand, that may easily be mistaken for the test 
of some Lituoline organism, like Webbina hemispherica or 
Placopsilina vesicularis. Many of the specimens of Polysto- 
