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THE VOYAGE OF H.M.S. CHALLENGER. 
(13) Cellepora tridenticulcita, n. sp. (PL XXIX. fig. 3, and PL XXXV. fig. 17). 
Character. — Zocecium lamellar, expanded, apparently unattached, uneven. Zocecia 
deeply immersed, surface shining, granular, imperforate. Orifice arcuate or subtrian- 
gular, with three, sometimes four, internal denticles within the lower border, and about 
0"'006-'007 wide. Rostrum (sometimes absent) a small rounded tubercle seated in a 
shallow depression, supporting on the summit, a minute avicularium with a semi- 
circular- mandible. A strong articulated spine on each side of the orifice. Large 
interspersed prehensile avicularia (fig. 36), apparently vicarious (certainly not rostral) ; 
usually immersed but sometimes more prominent and partially erect, with a short duck- 
bill shaped mandible, shutting down into a shallow boat-like beak, the edge of which is 
finely pectinate. 
Habitat. — Station 186, off Cape York, lat. 10° 30' S., long. 142° 18' E., 8 fathoms, 
coral mud. 
This well marked species is at once recognisable by the long articulated and 
indistinctly jointed oral spine on each side of the orifice. The limited development of the 
rostrum with its little imbedded avicularium is also a well marked feature, as is also the 
fine pectination of the border of the cup or beak in the interspersed avicularia. Another 
curious feature is the frequent occurrence on the surface of the zoarium of long- 
tubular processes or tunnels, looking like enormously elongated zooecia. The nature of 
these appendages appears very obscure. 
(14) Cellepora vagans, n. sp. (Pl. XXIX. fig. 10, and Pl. XXXV. fig. 11). 
Character. — Zoarium encrusting, of a dark olive colour. Zocecia small, with a single 
row of puncta round the border ; surface granular. Primary orifice (fig. 10a) orbicular or 
subclithridiate, the peristome much produced in front, with a wide sinus ; afterwards rising 
into a hollow, conical pointed rostrum, which usually supports on one side a minute 
avicularium, with a semicircular mandible. Numerous large interspersed avicularia, 
whose mandible (fig. 1 0c) sometimes expands at the extremity into three or four branches, 
connected by a delicate membrane, capable of being spread over foreign bodies, and is 
sometimes pointed, but always more or less membranous towards the end. 
Habitat. — Station 148, lat. 46° 47' S., long. 51° 37' E., 210 fathoms. Off Honoruru, 
Sandwich Islands, 20 to 40 fathoms. 
The peculiarities of this species arc : 1. The almost tubular production of the peristome 
even in the youngest zooecia ; 2. the peculiar conical pointed form of the preoral 
rostrum, which sometimes represents merely an obtuse tubercle, but is more commonly 
of an acute conical shape, the apical portion of which, being denuded of the dark fuscous 
