150 THE VOYAGE OF H.M.S. CHALLENGER. 
6, Madrepora manna, n. sp. (Pl. IX. figs. 11a). 
Corallum arborescent and loosely branched, somewhat prostrate ; the branches round, 
much elongated, about 2 cm. thick or more, gradually diminishing, and with few 
branchlets; branchlets simple, very elongated, often as much as 9 em, long, slightly 
tapering, about 15 mm. thick at the base and 6 mm. at the apex, ascending, arcuate, 
irregularly bent and generally springing from the upper surface of the oblique branches. 
Apical calicles not large, from 2 to 3 mm. wide, not prominent, with rather thick and 
scarcely porous edges ; star somewhat distinct, with six or twelve unequal, narrow septa. 
Lateral calicles extremely and broadly labellate, at right angles to the branch, very 
crowded ; fragile, so that the lips are easily broken away, leaving the stronger basal part ; 
more abundant, more prominent and stronger on the upper surface, becoming short and 
immersed on the basal part; the lip seldom flattened, generally curved, thin, and about 
2°5 mm. long, often as broad, though generally narrower and sometimes very small. A 
section of the cell across the base of the lip shows a very narrow aperture, about 0°5 
to 1 mm. wide, the immersed cells being of the same width; star inconspicuous. The 
ccenenchyma close and dense; the surface finely granulated and echinulated, and the 
calicles strongly striated. 
This form in its strongly marked characters differs from all other known species of 
the genus. It is named in honour of Dr. de Mann, late of the Leyden Museum, who 
first recognised its specific distinctness, but did not describe it. ts representative in the 
collection consists of a branched portion evidently broken from a large specimen. 
Locality.—Samboangan, Philippines. 
7. Madrepora nobilis, Dana. 
Madrepora nobilis et secunda, Dana, Zoophytes, p. 481, pl. xl. figs. 3, 4. 
Only a much branched portion of a specimen was obtained. It agrees closely with 
the form described by Dana as Madrepora secunda; but Verrill has stated that inter- 
mediate forms between this and Madrepora nobilis, which have been examined by him, 
show that they are one and the same species. In accordance with this observation of 
Verrill’s I have united the two species, though to judge by the description and figures 
given by Dana, they seem clearly distinct. 
Locality.—Kandavu, Fiji. 
8. Madrepora canalis, n. sp. (Pl. IX. figs. 2-26). 
Corallum arborescent, large, erect, loosely branched ; branches few, three or four often 
springing from the main stem at the same level, terete, about 2 em. thick or more, 
