180 THE VOYAGE OF H.M.S. CHALLENGER. 
2. Porites bulbosa, n. sp. (Pl. XI. figs. 7-7a). 
Corallum slightly incrusting at the base, much ramose ; branches rather short, thick, 
subterete or slightly compressed, sometimes coalescent, terminating above in much 
swollen, clavate knobs with truncated apex, often bifurcate and generally much constricted 
at the basal part of the knob. Calicles rather small, about 1°5 mm. wide, often less, 
superficial on the incrusting part, and slightly excavated above, never deep; in those 
calicles on the inner part of the corallum the walls are generally thin, with distinct septa, 
and a distinct circle of small pali enclosing a small styliform columella; in those on the 
outer part the walls are thick, from one-quarter to one-half the diameter of the cell, with 
a very distinct circle of larger and longer pali surrounding a larger columella, but the 
septa are much shorter, and less clearly distinct from the wall. The wall is reticulated 
and rather ragged, and the septa and pali are granulated. Texture firm, reticulated and 
porous, especially at the apical parts. 
This species though close to, is easily separable from Porites mordax. In the general 
form of the corallum it closely resembles Porites clavaria. It is represented by a fine 
and large specimen, the knobs of which are about 25 mm. thick, lessening to 15 mm. at 
the constricted part. 
Locality.—Reefs, Honolulu, and at depths of from 1 to 2 fathoms. 
3. Porites palmata, Dana. 
Porites palmata, Dana, Zoophytes, p. 558, pl. liv. fig. 3. 
A very fine example and some small fragments of this species were obtained. The 
cells are of very variable size, from 1 to 2°5 mm. wide; and the pali are distinct, long, thin, 
and prominent. 
Localities. —Samboangan, Philippines ; Amboina. 
4. Porites compressa, Dana. 
Porites compressa, Dana, Zoophytes, p. 553, pl. liii. fig. 5. 
The walls of the calicles throughout are very finely and raggedly spinulose, and owing 
to this the specimen is very rough to the touch. The septa are very granulated 
and spinulose ; the pali very distinct, small and generally elongated, and the columella 
elongated and distinct, though small. 
A single rather small specimen was obtained. 
Locality. — Honolulu. 
