106 THE ECHINODERMS OF TORRES STRAIT. 
(pl. 12, fig. 4) had the disk a little over 5 mm. across in life and the arms about 33 mm. 
long; dry, the disk is less than 5 mm. in diameter and the arms are all broken. The brown, 
bluish, and white coloration, so attractive in the living animal, is entirely lost in the dingy, 
pale brownish preserved specimens. In life, these brittle-stars were quite active, but they 
did not long survive their capture and transportation to the laboratory. In the largest 
specimen the thorns surmounting the disk stumps are fewer, longer, and themselves more 
thorny than in the smaller individuals. This may be a growth-change, but it is so marked 
that it is more probably indicative of individual diversity. This Ophiacantha is easily 
distinguished from the preceding species by the shorter, smoother, more opaque arm-spines, 
the larger upper-arm plates, the smaller adoral plates, and the very different disk-stumps. 
AMPHIURID/£E. 
Amphiura microsoma. 
H. L. Clark. 1915. Mem. M. C. Z., 25, p. 228, pl. 5, figs. 5-7. 
This is a rather aberrant member of the genus, somewhat allied to Ophionephthys, but 
as only two specimens are known, little more can be said at present. They were taken from 
a piece of coral brought up on the tangle from 4 to 5 fathoms of water, off the northwestern 
reef at Mer, October 7, 1913. They lived for some hours at the laboratory and after dark it 
was noticed that they exhibited a remarkable degree of phosphorescence when irritated. 
Amphiura septemspinosa. 
H.L. Clark. 1915. Mem. M.C. Z., 25, p. 231, pl. 4, figs. 13, 14. 
(Plate 13, Figure 3.) 
This very pretty little brittle-star was found in a crevice of a coral fragment on the 
southwestern reef at Mer. The colored figure shown on plate 13 is twice natural size, but 
shows well the colors in life, save that the general effect is a little redder than was the 
ophiuran itself. While presumably this specimen was immature, specific characters are 
already well marked. 
Amphiocnida dilatata. 
Ophiocnida dilatata Koehler. 1905. Siboga Oph. litt., p. 30, pl. xii, figs. 2-4. 
Amphiocnida dilatata H. L. Clark. 1915. Mem. M. C. Z., 25, p. 236. 
(Plate 16, Figure 7.) 
Thisinteresting and peculiar brittle-star was previously known only from four widely scat- 
tered stations in the Sulu Archipelago, Celebes, and the Aru Islands. A single specimen was 
found at Mer, in a cranny in the corals of the southwestern reef October 23, 1913. The pecu- 
liar shape of the arms was noticed in life and the unusual coloration also attracted attention. 
Ophionephthys octacantha. 
H. L. Clark. 1915. Mem. M. C. Z., 25, p. 239, pl. 9, figs. 9, 10. 
(Plate 15, Figure 3.) 
The pretty coloration of this curious brittle-star has changed greatly since it was 
first taken. The striking blue bands on the arms have become blackish, and the brown and 
yellow shades have lost their brightness. The arms were very brittle in life and not one 
was complete when the specimen was found under a stone on the sand flat southwest of 
Friday Island, Torres Strait, September 13, 1913. 
Amphipholis squamata. 
Asterias squamata delle Chiaje. 1828. Mem. Anim. s. Vert. Napoli, 3, p. 74. 
Amphipholis squamata Verrill. 1899. Trans. Conn. Acad., 10, p. 312.—H. L. Clark. 1904. Bull. U. 8. Fish 
Comm., 1902, p. 560, pl. 6, figs. 38, 34; pl. 7, figs. 43, 44. 
The discovery of this cosmopolitan species on the reef-flat at Mer was quite a surprise. 
It was not common, only four specimens being found altogether, but these are not distin- 
