102 J. Armstrong—A Description of some new species of [No. 2, 
where alone they are adnate, being narrower at the orifice, which is square, 
and has the margin produced into four nearly equidistant teeth, they are 
all more or less deeply annulated or spirally ribbed. 
Gonosome.—Unknown. 
Habitat.—Off Cape Comorin in 40 fathoms, and off the Arrakan 
Coast in from 10 to 15 fathoms. 
This hydroid bears a very close resemblance to 8. tenella of Alders, 
but differs from it in the stem not being twisted at the joints and in the 
spiral ribbing of the hydrothece. 
THIMARIA COMPRESSA (nov. spec.) 
(Plate XII.) 
Trophosome.—Stems sparingly clustered, about an inch and a half 
in height, unfascicled, erect, more or less decidedly zig-zag, rooted by a 
creeping tubular stolon, and giving origin to a limited number of pinne. 
The pinne are alternate, few in number, and arise at regular intervals 
from the main stem, of which they are for a short part of the commence- ~ 
ment of their course mere diverticula, being identical with it in structure, 
destitute of hydrothece, and with two annular constrictions marking the 
origin ofeach. The terminal nine-tenths of its length is made up of an aggre- 
gation of closely packed subalternate hydrothee, which are continued 
to its termination. Very often, however, the pinna is composed of a linear 
series of two or sometimes of three of the simple forms above described. 
The lower half of the hydrotheca is broadly tubular and adnate, the 
upper half is narrower, free, and projecting horizontally outwards, the 
aperture is oblique with the lower margin prolonged into a sharp tooth. 
Gonosome.— Unknown, 
Habitat.—Extremely abundant on the rocks between high and low 
water at Diamond Island, as well as amongst the laterite rocks on the 
Konkan Coast. I have also dredged it in 40 fathoms of water off Cape 
Comorin. 
ANTENNELLA ALLMANNI (nov. spec.) 
(Plate XIT.) 
Trophosome.—Stems sparingly clustered, very slender, gently curved 
from base to apex, rooted by a slender filiform stolon, and attaining a 
height of about half an inch; they are divided by long, oblique partitions 
into a series of internodes, each of which carries an hydrotheca and four — 
nematophores. The hydrothece are campanulate with large patulous 
orifices and perfectly even slightly everted margins. The nematophores — 
are four in number on each segment of the stem, two lateral, one inferior | 
and one superior. The lateral nematophores are quite free, long, narrow, 
and trumpet-shaped with a circular aperture and everted margin, from 
which they gradually taper down to extremely fine points, which are at-— 
