OF THE ‘ PORCUPINE’ EXPEDITIONS. 473 
This species has a peculiar habit, caused by its long, rather distantly disposed, flexile 
branches, which give it a loose diffuse character, by which it contrasts with the closer 
and more compact habit of other species. 
It was obtained from the cold area lying between Shetland and the Faroe Isles, in two 
dredgings—one at 640 fathoms, where the bottom had a temperature of 30° Fahr., and 
the other at 363 fathoms, with a bottom-temperature of 30°6 Fahr. 
THUIARIA HIPPURIS. Plate LXV. figs. 2, 2°. 
Trophosome.—Stem attaining a height of about six inches, slightly zig-zag, except 
towards its base; its proximal end for about one sixth of its entire length destitute 
of branches, annulated irregularly at the base, and with joint-like annuli at irregular 
intervals for some distance upwards ; branches repeatedly dividing dichotomously so as 
to form fan-shaped groups. Hydrothece on the main stem scattered, on the branches 
alternate ; those in each series separated from one another by a distance of little more than 
two thirds of their height; orifice semicircular, provided with a valve-like operculum. 
Gonosone not known. 
Thuiaria hippuris has somewhat the aspect of T. thuia, from which, however, it differs 
by its less crowded ramuli and more distant hydrothecee, as well as by its more attenuated 
and flexile stem. 
It was dredged in the deep cold area between Shetland and the Faroe Isles, along with 
Thuiaria laxa, from a depth of 640 fathoms, where the temperature of the bottom was 
as low as 30° Fahr. 
THUIARIA SALICORNIA. Plate LXV. figs. 3, 3%. 
Trophosome.—Stem attaining a height of about two inches, jointed at rather irre- 
gular intervals, simple or sparingly branched, somewhat rigid, with pinnately disposed 
branchlets above, destitute of branchlets below; pinne alternate, about four lines 
in length, articulated to projections of the stem. Hydrothece flask-shaped, alternate, 
immersed for the greater part of their depth, but becoming free at a short distance 
from the orifice, simply distichous on the main stem, and with the axes of all the 
hydrothece in each row turned in the same direction, but on the pinne having their 
axes alternately directed to the right and left, so as to give them here an apparently 
tetrastichous arrangement. 
Gonosome not known. 
The alternating directions of the axes of the hydrothece composing each row of the 
pinnz confer on this species a striking physiognomy. 7’. salicornia further differs from 
other species of Thuwiaria in the less complete immersion of the hydrothece, and from 
most species in its simple pinnately disposed ramuli. It was obtained west of the Faroe 
Isles, in lat. 62°, long. 5° 30', at a depth of 114 fathoms. 
