18 
THE VOYAGE OF H.M.S. CHALLENGER. 
The general structure of this species is very peculiar, and together with other 
characters might perhaps justify its erection into a distinct genus. The cells, different from 
those of nearly all the other Cellulariadse, are entirely open in front, and of equal width 
throughout below the immediate summit, which is contracted to the width of the crescentic 
mouth. They are seen to arise, when viewed from behind, by a very broad base, from 
the side as it were, of the subjacent cell. The consequence of this is that they are all 
placed obliquely with respect to the axis of the branch, standing out on either side with 
extreme regularity. The only specimen in the collection is about three inches high, and 
the curling branches form a thick entangled tuft, very difficult to unravel. The main 
stem is of considerable thickness, and composed of a closely packed bundle of radical tubes, 
which at the lower extremity break up into innumerable and very fine jointed filaments, 
each of which becomes attached to a Globigerina- shell, or other small solid particle, the 
whole forming a thick floccose tuft, composed of the fibres and attached particles. 
(4) Cellularia quadrata, n. sp. (PI. V. fig. 5). 
Character. — Ten to fourteen zooecia in each internode, biserial, the two series facing 
different ways at a slight angle. Zooecia quadrate, entirely open in front, the aperture 
slightly contracted by a very narrow lamina. Surface of border and lamina very delicately 
frosted. Dorsal surface smooth entire. A small lateral avicularium slightly in front of 
the superior angle. 
Habitat. — Station 149 d, Eoyal Sound, Kerguelen, 28 fathoms, volcanic mud. 
Station 151, Heard Island, 75 fathoms, volcanic mud. 
Closely allied, apparently, to Meni'pea ornata, but differs from it in the much less 
developed lamina, and the absence of any anterior avicularia, anct the more elongated form 
of the cells, which in the former species are nearly square. 
§ /3. fornicates. 
(5) Cellularia biloba, n. sp. (PI. III. fig. 2). 
Character. — Zoarium lax, straggling, branches very slender. Zooecia trumpet-shaped. 
Orifice oval, with a much raised crateriform border. Four or five slender, oral spines, and 
a bilobed pedunculate fornix. A small avicularium situated quite behind the angle of 
every zooecium, with an acute mandible pointing downwards. 
Habitat. — Station 76, lat. 38° 11/ N., long. 27° 9' W., 900 fathoms, Pteropod ooze. 
The avicularium is entirely posterior, and is not visible in a front view; and it is quite 
immersed. 
