■REPOET ON THE EORAMINTEEEA. 
259 
tlie broad end, the remainder forming a tube of nearly even diameter. Walls thick and 
loosely arenaceous ; exterior surface rough, interior tolerably smooth. Length, -A-th inch 
(15 or 16 mm.). 
4 
The large arenaceous specimens constituting the present species were originally 
included with some of the smaller forms under the general appellation Hyperammina 
elongata, but further research has led to the conclusion that both in zoological characters 
and distribution they pertain to a distinct and easily recognised modification of the type. 
The following are the more important distinctive features. Average specimens of 
Hyperammina friabilis are of larger dimensions, and in general contour are much broader 
and stouter than corresponding examples of Hyperammina elongata ; compare fig. 3 
with fig. 7. The consistence of the test in the former is loose, and the sand grains are 
easily disintegrated ; that of the latter hard and firmly cemented. Comparing the 
sections, figs. 5 and 6, with fig. 10, the walls of Hyperammina friabilis are conspicuously 
thick and the cavity has a well-marked primordial chamber, whilst Hyperammina elongata 
has uniform and thin walls, and the cavity is only slightly widened at the inferior end. 
Hyperammina friabilis is often of grey rather than brown colour externally, but is more 
or less stained on the interior surface and around the mouth. 
The geographical distribution of Hyperammina friabilis is very restricted, as com- 
pared with that of Hyperammina elongata. Judging from the “ Porcupine ” collections, 
it is not uncommon in some parts of the warm area of the Faroe Channel, at depths of 
from 540 fathoms to 767 fathoms ; and it has been found at two other Stations in the 
North Atlantic, namely, south of Rockall Bank, 630 fathoms, and off Culebra Island, West 
Indies, 390 fathoms. In the South Atlantic it occurs at two Stations off the coast of 
South America, near Pernambuco, 675 fathoms and 350 fathoms respectively ; and 
lastly, if we except a single broken specimen in one of the dredgings between Australia 
and New Zealand, at one Station in the Indian Archipelago, off Amboy na, 1425 fathoms. 
Hyperammina subnodosa, n. sp. (PI. XXIII. figs. 11-14). 
Test long, cylindrical, constricted at irregular intervals ; primordial end closed and 
rounded ; opposite extremity, either entirely open or somewhat contracted, serving as the 
aperture ; the interior forming a tube of uneven diameter, commencing in a subspherical 
chamber, and more or less distinctly segmented. Walls thick, except at the primordial 
end, where the test is often comparatively thin ; texture coarsely arenaceous. Length, 
fth inch (18 mm.) or less. 
The external contour of Hyperammina subnodosa is well displayed in PI. XXIII. 
fig. 11, which is drawn from a large and characteristic specimen. The repeated con- 
striction of the tube, and the incomplete segmentation of the cavity induced thereby, are 
