130 THE ECHINODERMS OF TORRES STRAIT. 
more of these is not in any sense a natural group and should have no distinctive name, 
while on the other hand it is quite possible that at least one is really a distinct species. 
There is no doubt that the form to which Peters first gave the name brevipes is the rela- 
tively small (15 to 18 mm. across the disk) variety, in which the arms are only 3.5 to 4.5 
times the disk-diameter; there are 5 to 7 arm-spines on the basal joints, and there is more 
or less green or greenish in the light coloration. This typical form occurs all through the 
Indo-Pacific region from Zanzibar to Hawaii, north to southern Japan, and south to Green 
Island, Queensland. At Mer it was rather common on the northeastern reef-flat on the 
sand under coral fragments. In life the lower surface has often a distinctly reddish tinge. 
Ophiocoma brevipes var. variegata. 
Ophiocoma variegata E. A. Smith. 1876. Ann. Mag. Nat. Hist. (4), 78, p. 39.—1879. Philos Trans., 168, p. 
565, pl. li, figs. 1-1c. 
Ophiocoma dentata Liitken. 1859. Add. ad Hist. Oph., pt. 2, p. 165 (non Miiller and Troschel). 
ea Marktanner-Turneretscher. 1887. Ann. K. K. Natur. Hofmus. Wien, 2, p. 303, pl. xii, 
Galena déderleini de Loriol. 1899. Mém. Soe. Phys. Hist. Nat. Genéve, 33, pt. 2, No. 1, p. 30, pl. iui, fig. 2. 
This is the large, variegated form of brevipes, lacking green in the coloration, and hav- 
ing the arms a little longer relatively, often five times the disk-diameter. Adult specimens 
are 20 to 25 mm. across the disk. There is great diversity in the color-pattern, the basal 
shades of which are blackish, gray, brown, and dirty white; the most striking forms are 
those with the disk handsomely reticulated (dentata Liitken) and with the disk regularly 
sprinkled with small blackish spots (déderleini de Loriol). The arms are commonly more 
or less distinctly banded with light and dark shades. Specimens before me with a green- 
ish tinge seem to connect this form with typical brevipes, but I shall not be surprised if 
each form proves to be a valid species. At Mer variegata is very common, especially on 
the southeastern flat. One specimen was taken which seemed to be a true albino, as it 
was uniformly whitish; unfortunately it became stained in the preserving fluid and is now 
a dingy brownish rather than white. This form of brevipes occurred at Mer, oftentimes near 
high-water mark in the zone where scolopendrina occurred, but it was not by any means 
confined to that region. We found it common at Erub, and it also occurred at Green 
Island, near Cairns. There are specimens in the Museum of Comparative Zodlogy from 
Lord Howe Island, from Zanzibar, from Mauritius, and from the Pelew Islands. Some 
very young brevipes from the Hawaiian Islands may be variegata, but it is not unlikely 
they are the young of var. insularia. 
Ophiocoma brevipes var. insularia. 
Ophiocoma insularia Lyman. 1861. Proc. Boston Soc. Nat. Hist., 8, p. 80.—H. L. Clark. 1915. Mem. 
M. C. Z., 25, p. 291, pl. 15, figs. 3, 4. 
Ophiocoma ternispina von Martens. 1870. Arch. f. Naturg., Jhrg. 36, 7, p. 252. 
Ophiocoma tenuispina (err. typ.) de Loriol. 1894. Mém. Soc. Phys. Hist. Nat. Genéve, 32, pt. 1, No. 3, p. 27. 
This is a well-marked form bearing much the same relation to var. variegata that 
erinaceus does to scolopendrina. It is characteristic of the Pacific region, for while von 
Martens’ type of ternispina was from Flores and there is a typical specimen of insularia 
in the Museum of Comparative Zodlogy from Tanegashima, Japan, all the other specimens 
I have seen are from Hawaii, the Society Islands, and Easter Island. It seems to be the 
only Ophiocoma occurring so far to the southeast as Easter Island, excepting only the 
following closely related variety, longispina. In size, insularia becomes the largest of the 
brevipes group, a specimen from Hawaii measuring 32 mm. across the disk. The uniformly 
blackish color and the presence of only three rather long and slender arm-spines beyond 
the basal joints of the arms make the recognition of insularia easy. We did not meet 
with it in the Torres Strait region. Specimens from Easter Island are lighter colored than 
usual and tend to have banded arms. 
