60 
THE VOYAGE OF H.M.S. CHALLENGER. 
The zoarium, though spreading in a lobate manner over other foliaceous Polyzoa, does 
not appear to have any real attachment to them. In the description given in Brit. Mus. 
Cat. it is stated that there is no movable mandible in the curiously formed oral 
appendages, but in reality these organs consist of a hollow conical membranous bag, 
whose base looks forwards and downwards, and is closed by a semicircular membranous 
lid, which clearly represents the mandible of an avicularium. When collapsed, these 
appendages assume the figure represented in Brit. Mus. Cat. 
(3) Diachoris costata, Busk (PI. XXXJY. fig. 4). 
Diachoris costata, Bk., Kerguelen Island Polyz., p. 3, pi. x. figs. 5, 6. 
Character. — Zoarium very loosely attached, and spreading irregularly. Zooecia 
decumbent in straight rows radiating from central points ; elongate fusiform, front 
entirely covered with numerous ribs, sometimes forked at the end, and interdigitating in 
the mesial line. Orifice semicircular, lower lip straight, entire; four unarticulated oral 
spines, two above and one on each side. An articulated, capitate avicularium on 
one side a short distance from the top ; the beak much curved and projecting beyond the 
acute crooked mandible. 
Habitat. — Station 315, lat. 51° 40' S., long. 57° 50' W., 5 to 12 fathoms, sand and 
gravel. 
[Queenscliff, Victoria, Wilson; Royal Sound, Kerguelen, Eaton.] 
(4) Diachoris inermis, Busk. 
Diachoris inermis , Bk., Brit. Mus. Cat., vol. i. p. 54, pi. lxxii . ; Hutton. 
Character. — Zooecia decumbent, boat-shaped, entirely open in front. Two short 
marginal spines on each side above and a variable number of small incurved spicules on 
each side of the orifice. No avicularia. 
Habitat — Station 149d, Royal Sound, Kerguelen, 20 to 60 fathoms. 
[New Zealand, Dr. Lyall ; Strait of Magellan, Darwin.] 
In the Brit. Mus. Cat. no mention is made of the fine lateral spicules, but as in all other 
respects the form there intended is identical with the present, this difference cannot be 
regarded as of any consequence. 
