152 THE VOYAGE OF H.M.S8. CHALLENGER. 
their irregularly bent and divergent forms, and the apical bunch of proliferous branchlets 
on the large specimens, give a peculiar appearance to the corallum. It closely resembles 
Madrepora abrotanoides, and may ultimately prove to be only a well-marked variety 
of that species. 
Locality.—Tahiti. 
11. Madrepora austera, Dana. 
Madrepora austera, Dana, Zoophytes, p. 478. 
The specimen of this species consists of a broad, low clump, which has evidently grown 
under peculiar conditions. The base has formed on one side a solid massive piece, while 
on the other sides it has grown incrusting over a mass of dead coral. The branches are 
short, thick, and very proliferous, and many of them have been broken during growth. 
The surface is very rough, reticulated and echinulate. The lateral calicles are harshly 
striated, frequently dimidiate, or tubo-nariform, with a very elongated aperture, very 
unequal, often proliferous, and becoming immersed on the basal parts of the branches 
and on the incrusting base. On the upper parts of the branches and branchlets immersed 
cells do not occur as numerously as in Madrepora abrotanoides, but they are often 
present in large numbers on the under side, 
Locality. —Mactan Island, Philippines. 
12. Madrepora scabrosa, n. sp. (Pl. X. figs. 2-2e). 
Corallum fruticose, much branched, closely crowded, and proliferous, attaining a very 
large size; the branches subterete, thick at the base, often as much so as 3 cm., ascend- 
ing, arcuate or irregularly bent, but not divaricate ; branchlets subattenuate, often much 
elongated, but generally short, especially at the exterior basal part, where they are thick, 
irregular, and almost spike-shaped. Apical calicles about 3 mm. wide, prominent, with 
thick, somewhat porous edges, and a distinct star of twelve unequal, narrow septa, which 
meet deep down in the cell. Lateral calicles rather appressed, very unequal, often 5 mm. 
long ; scarcely crowded above, where they are tubiform and long, quickly becoming tubo- 
nariform and rostrato-nariform ; crowded below, short, rostrato-nariform, and round- 
nariform, rarely proliferous, and almost or completely immersed on the basal parts ; 
many very short and small cells occur between the prominent ones, opening sideways or 
downwards ; and numerous, long, tubiform cells on the upper branches and branchlets 
become proliferous with short calicles along their under side, remaining bare on their 
upper side during a long period of growth ; the aperture of the cell is large, round below 
and oblong above, with the lower side very rough and generally finely spinulose ; star 
