126 
THE VOYAGE OE H.M.S. CHALLENGER. 
Among the chitinous parts in this species I have occasionally noticed one of the 
peculiar form shown at the top of the figure — the nature of which is obscure. 
(23.) Retepora magellensis, n. sp. (PL XXXVI. fig. 20). 
Character. — Zoarium infundibuliform or cupped, rising from a short thick peduncle. 
Fenestrse elongate oval, pointed at each end about 0 //- l x '05, rather narrower than the 
trabeculae. Surface both before and behind finely granular and glistening. No dorsal 
or fenestral avicularia and no vibices. Zooecia elongate, ovate, convex, and distinct in 
the younger parts. Orifice contracted, primarily clithridiate, peristome, not thickened, 
with a short submedian fissure and small pore, and a labial avicularium on one angle ; 
four to six slender oral spines visible only in the youngest cells. Operculum semicircular, 
with a thick rim, about 0"'012 x '01, and often having two lemniscus-like sacculi depen- 
dent behind the lower border. Avicularian mandible, with very strong occlusor 
muscles, and an elongated lemniscus-like sacculus between them. 
Habitat. — Station 320, 37° 17' S., 53° 52' W., 600 fathoms, green sand. 
[Falkland Islands, Miss Gatty]. 
2. Reteporella, n. sub-gen. 
Character. — Those of Retepora, but the branches free in one plane. 
(1) Reteporella jlabellata, n. sp. (PI. XXV. fig. 5). 
Character. — Zoarium flabellate, about 1"’5 high, and wide ; composed of dichotomous 
branches, diverging from a thick common peduncle, attached to coral by a calcareous non- 
celliferous expansion. Zooecia (young) ovate, convex ; surface granular, 
glistening, pearly. Orifice orbicular. Peristome thick, annular, slightly 
raised ; a rather long labial fissure terminating in a large pore. From 
one to three broad, flattened, lanceolate, antenniform, articulated spines 
on one or both sides. Anterior avicularia on tubercular eminences, 
seated on the lower part of most of the zooecia ; mandibles, very delicate, 
membranous. No dorsal avicularia. Dorsal surface, showing the 
outlines of the zooecia, pearly, granular, not vibicate. Ooecia 0 (?) 
Habitat. — Station 151, off Pleard Island, 75 fathoms, volcanic mud. 
Fig. 38 . — Reteporella 
Jlabellata. 
Only a single specimen of this interesting form occurs in the 
•collection. In the lower parts of the zoarium the surface is almost smooth and entire, 
nearly all traces of the individual zooecia being completely obliterated. 
