138 THE ECHINODERMS OF TORRES STRAIT. 
corals or under rocks. It is very active, and climbs about rapidly (for an echinoderm) 
between the branches of the coral colonies. Although so similar to caryophyllata, it is 
perfectly distinct from that species, the form of the upper arm-plates (pl. 36, fig. 11) and 
the very different color-pattern preventing any confusion of the two. The largest speci- 
men seen is 18 mm. across the disk. 
Ophiomastix venosa. 
Peters. 1851. Monatsb. K.-Preuss. Akad. Wiss. Berlin, p. 464.—Koehler. 1904. Mém. Soe. Zool. France, 
17, p. 73, figs. 28, 29. 
The geographical isolation of this species on the eastern coast of Africa is notable. 
It has been recorded from Mozambique, Zanzibar, and Madagascar. Bell asserts (1902) 
that it is common in the Maldives, but as it is not known from Mauritius or the Seychelles, 
it seems to me its occurrence at the Maldives requires confirmation. It is the heaviest 
species of the genus, 30 mm. across the disk when adult, with arms about 150 mm. long, 
noticeably stout and with relatively short, thick spines. The disk spinules are few, some- 
times occurring only at the disk-margin; they are short, thick, and blunt. 
Ophiomastix variabilis. 
Koehler. 1905. Siboga Oph. Litt., p. 69, pl. vi, fig. 16; pl. xvi, figs. 3, 4. 
This species is known only from the Siboga specimens, which were taken at four widely 
separated stations in the Dutch East Indies. They show great diversity in disk-spinula- 
tion, but agree in the characteristic light markings about the radial shields. The largest 
specimens are only 6 to 7 mm. across the disk, with arms 40 to 45 mm. long, so it is evi- 
dent that adult material will throw new light on the status of the species. 
Ophiomastix ornata. 
Koehler. 1905. Siboga Oph. Litt., p. 71, pl. vi, figs. 13, 14. 
The unique holotype of this species was taken on Borneo Bank by the Siboga. It is 
only 9 mm. across the disk and all the arms are broken. Adult material is therefore needed 
even more than in the case of variabilis. 
Ophiomastix bispinosa. 
H.L. Clark. 1917. Bull. M.C. Z., 61, p. 442, pl. 2, figs. 1, 2. 
This is another inadequately known species, of particular interest because of its being 
the easternmost representative of the genus. The unique holotype, only 5 mm. in disk- 
diameter, with arms 40 to 45 mm. long, was taken at Makemo in the Paumotus. 
Ophiomastix flaccida. 
Ophiomastix flaccida Lyman. 1874. Bull. M. C. Z., 3, p. 226, pl. vi, figs. 14, 15. 
Acantharachna mirabilis Smith. 1878. Jour. Linn. Soe. Zool., 13, p. 335, pl. xviii, figs. 1-6. 
(Plate 13, Figure 2.) 
I should not have dared identify with this species the little brittle-star found at Mer, 
October 8, 1913, and figured on plate 13, had I not had for comparison a small paratype 
from the Philippine Islands. The Murray Island individual was scarcely 4 mm. across 
the disk and had arms only about 18 mm. long. The disk was bluish with some orange-red 
lines, the arms yellow with dark-green marks along the sides and the arm-spines white. 
There are no disk spinelets, but on each arm are a number of claviform spines, and as there 
are no tentacle-scales I am satisfied that the individual is a very young flaccida. The 
species is otherwise known from the Philippine Islands, many stations in the Dutch East 
Indies, and the island of Salawatti, New Guinea. Studer (1883) says the species lives on 
sponges and is purplish-red in life. The largest specimen in the Museum of Comparative 
