140 THE ECHINODERMS OF TORRES STRAIT. 
Ophiarthrum pictum. 
Ophiocoma picta Miller and Troschel. 1842. Sys. Ast., p. 102. 
Ophiarthrum pictum Lyman. 1874. Bull. M. C. Z., 3, p. 225, pl. vii, figs. 2-4. 
(Plate 12, Figure 1.) 
This is unquestionably one of the most beautiful of brittle-stars, though its beauty is 
quite different from that of Ophiarachna incrassata. In the present species, the colors are 
light and in life many of the tints are very delicate; few if any remain unchanged in pres- 
ervation. As shown in the figure (pl. 12, fig. 1), white, pearl-gray, and yellow are the 
principal colors, but a darker shade of gray forms a more or less complete median longi- 
tudinal stripe on the upper side of the arm. There is considerable individual diversity in 
the color-pattern of the disk, but the 5 white interradial areas with their curious yellow 
marks are generally very distinct. The white is often distinctly tinted with blue. The 
largest specimen I have seen is 30 mm. across the disk, and specimens 20 to 25 mm. across 
are common; the arms are 5.5 to 8 times the disk-diameter. 
This species has a much more restricted range than the preceding. The type locality 
is Java, and it has not been found west of that island. It is common at Amboina and 
is known also from several other stations in the Dutch East Indies, from the Philippines, 
from Timor, and New Guinea, and from the Pelew Islands. At Mer we found pictum 
fairly common on the southeastern reef-flat, where it lives under rock and coral fragments. 
Like elegans, it is a moderately active and rather delicate brittle-star, but it stood handling 
and transportation to the laboratory rather better than the smaller species. 
Ophiarthrum lymani. 
De Loriol. 1894. Mém. Soe. Phys. Hist. Nat. Genéve, 32, pt. 1, No. 3, p. 34, pl. xxiv, figs. 2-2d. 
This is one of the endemic echinoderms of Mauritius, known only from de Loriol’s 
account. It is about the same size as elegans, but has relatively shorter arms, as these are 
only a trifle more than five times the disk-diameter. The coloration is the obviously dis- 
tinguishing species character. One can not determine from de Loriol’s account whether he 
had more than a single specimen. 
OPHIODERMATID£E. 
Ophiarachna incrassata. 
Ophiura incrassata Lamarck. 1816. Anim. s. Vert., 2, p. 542. 
Ophiarachna incrassata Miiller and Troschel. 1842. Syst. Ast., p. 104.—Herklots. 1869. I[chinod. peintes 
d’aprés Nature, pl. vi (colored). 
(Plate 34, Figures 1 and 2.) 
The type locality of this superb ophiuran is unknown, but Miiller and Troschel give 
Java as its home. It has been recorded from Zanzibar, Darros Island, and Ceylon on the 
west and from the Caroline and Fiji Islands on the east; on the north it reaches the Riu 
Kau and Bonin Islands, while on the south Green Island, Queensland, seems to be the limit 
of range. It occurs throughout the Torres Strait region, being common at Badu, Erub, 
and Mer. It is the largest known simple-armed ophiuran, mature specimens having the 
disk 40 to 50 mm. across. The largest specimen I have seen is 57 mm. in disk-diameter. 
The arms are rather short and stout, 3.5 to 4 times the width of the disk. The coloration 
is as remarkable as the size and would scarcely be guessed at from preserved specimens. 
The ground-color is a brilliant grass-green, upon which are white spots encircled with black, 
and occasional black spots and markings; the arm-spines, particularly the lower ones, are 
handsomely annulated with black and white. All in all, incrassata is one of the handsomest, 
if not actually the most beautiful, of all brittle-stars. Unfortunately, the green is very 
fugacious, and preserved specimens, no matter how carefully or by what method prepared, 
rarely retain even a hint of it. It is replaced by a pale brown or dirty yellow which may 
fade to light yellow or nearly white. 
