100 J. Armstrong—A Deseription of some new Species of [No. 2, 
nematophores are three in number, two lateral, which are short, blunt, 
divergent, and projecting slightly beyond the margin of the hydrotheca ; 
and one mesial, which is remarkable as being provided with a lateral as 
well as terminal orifice, it is adnate to the base and lower third of the 
calycle, being free only at its extremity which projects horizontally out- 
wards from the hydrotheca. 
Gonosome.—Consists of a number of lozenge-shaped bodies filled 
with dark granular matter, and pointed at their free extremities; they 
arise on each side of the primary pinne in the intervals between the 
ultimate pinne. , 
Habitat.—Off Cape Negrais in 80 fathoms. At Cheduba Island 
in from 8 to 10 fathoms ; off the Terrible Islands in 25 fathoms, and off 
Cape Comorin in 40 fathoms. 
This beautiful species is closely allied to Halicornaria bipinnata of 
Allman. It has a very wide distribution, being found at intervals all 
along the Arrakan and Pegu Coasts, as well as off the South Coast of 
India. On several specimens which I examined I found the main stem 
provided with two parallel rows of pellucid dots, the nature of which 
I have hitherto been unable to determine ; they are, however, most probably 
the optical expression of cauline nematophores. It is also remarkable 
in having the mesial hydrothecal nematophore provided with a lateral 
orifice asin HZ. saccaria (Linn. Soc. Journ., Vol. XII.) This species appears 
to afford a favourite anchoring ground for a small bivalve belonging to the 
genus “ Vexillum ;” most of the specimens dredged up by me were covered 
with this species firmly adherent by their byssiand in different stages of 
development, 
HALICORNARIA PLUMOSA (nov. spec.) 
(Plate XI.) 
Zoophyte.—Feathery, gregarious, 
Trophosome.—Stems one to two inches in height, fascicled towards 
the base, of a dark brown colour, straight or gently curved, minutely 
pinnate and rooted by a creeping filiform stolon, The pinne arise alter- 
nately by jointed processes from the anterior surface of the stem; they 
are divided by more or less complete joints into a series of short internodes, 
each of which carries a calycle with its nematophores. The hydrothece 
are unilateral and borne on the upper surface of the pinne and sessile ; 
they are cup-shaped and have a large and patulous orifice, the margin of 
which is deeply denticulated, and is especially characterized by the pos- 
session of a single long mesial tooth immediately behind and projecting 
above the anterior nematophore. The intrathecal ridge passes backwards 
