124 
THE VOYAGE OF H.M.S. CHALLENGER. 
(19) Retepora phaenicea, Busk. 
Retepora phoenicea, Bk., Brit. Mus. Cat., vol. i. p. 94, pi. cxxi. figs. 1, 2. 
Character . — Zoarium folded, expanding, much convoluted; of a purple colour. 
Zooecia ovate, ventricose. Orifice prominent, circular, sometimes subtubular. Border 
entire or irregularly serrate. Baised interzocecial septal ridges. Anterior avicularia 
sparse, placed obliquely on the front, close below the orifice, with an 
acuminate mandible very wide at the base. Ooecia immersed (when 
young having in front a concentrically marked operculum). 
Habitat. — Station 162, off East Moncceur Island, Bass Strait, 38 
fathoms, sand, shells. 
[South Australia, Adelaide, Glenelg, Hincks.] 
I have placed Retepora phoenicea with the species furnished with a trifoliate stigma, 
considering that the stigma is represented by the sort of operculum with which its 
ooecium is at one time furnished, and which is probably of the same nature as the stigma. 
§§ 4. Ooecia inconspicuous or unknown. 
(20) Retepora delicatula, n. sp. (PL XXVI. fig. 3). 
Character. — Zoarium about 0"*5 high, cup-shaped, springing from a central point, but 
without any actual peduncle. Fenestras oval, uniform. Zooecia broadly ovate. Orifice 
wide, orbicular. Peristome raised and canaliculate in front, expand- 
ing on the sides. Anterior lip with a lateral fissure, terminating in 
a large rounded pore. On one side of the fissure an extremely 
minute avicularium, on a small tubercular thickening of the angle. 
From 1 to 3 oral spines, sometimes obscurely jointed on each side. 
Ooecia inconspicuous. Anterior avicularia extremely rare ; seated on 
¥ia \fd~Ma P ° ra short conical processes. Mandible triangular, obtuse, pointing for- 
wards ; dorsal or rather fenestral avicularia deeply immersed ; the 
mandible, which is deeply sunk, is long, slender, and usually furcate, pointing directl)? 
downwards. 
Habitat. — Station 190, lat. 8° 56' S., long. 136° o' E., 45 fathoms, green mud. 
The furcate fenestral avicularian mandible is something like that of Retepora 
fubulata and Retepora columnif era, but the limbs of the fork are wider, shorter, and 
pointed instead of being obliquely truncated. A special group might perhaps be made 
of the species having furcate retentive mandibles. There are several besides those in 
the Challenger Collection, and all probably Australian or New Zealand forms. 
Pig. 34. — Retepora. 
phcenicea. 
