134 THE ECHINODERMS OF TORRES STRAIT. 
and the latter may lack claviform arm-spines and even disk spinelets. It is therefore diffi- 
cult to identify certainly very small specimens, unless they are actually taken with adults. 
The genus Ophiomastix has its center of abundance in the East Indian region. The 
Siboga took 7 species, and we found 7 species at Mer, 5 being common. Only one species 
occurs on the east coast of Africa, and is otherwise known only from Madagascar and the 
Maldives. No species is recorded from Mauritius. One species occurs at Ceylon, 3 are 
listed from the Philippines, 3 from the Riu Kiu Islands (one extending northward to Tokyo 
Bay), 3 from Fiji, and 1 from the Paumotus, but none are yet recorded from the Hawaiian 
Islands. It is most remarkable that the genus, while so common at Mer, is quite unknown 
from the mainland coast of Australia and from the Thursday Island region. 
Brock (1888) gave special attention to Ophiomastiz and published two important 
tables of the species, one based on the claviform spines and the other on the disk-covering. 
In neither, however, does he make sufficient allowance for individual diversity or for 
growth-changes. It is hoped that the following key will prove more elastic. 
Key to the Species of Ophiomastiz. 
A. Tentacle-scales present. 
B. Disk covered with granules, some of which are elongated into spinelets; the gradation between 
granules and spinelets may be obvious or the latter may be abruptly distinct; 
arms relatively short, about 5 times disk-diameter. 
C. Tentacle-scale single, except often on basal pores; colors black (or dark gray) and white (or 
VLOG IA) NSS Hee ERS er ae OES ER IIRC A EG ers MED sere Bee eed og ona on oreee asperula 
CC. Tentacle-scales 2. 
Color in life uniformly deep red; preserved specimens are orange, yellow, cream-color, 
brownish; or prayish> withoutumarkings .2-.sc. ces eee ao eeiaer cree mixta 
Colors, brown variegated with lighter; arm-spines ringed with light and dark....... elegans 
BB. Disk bare but with more or less numerous, scattered spinelets, and sometimes a few coarse 
granules. 
C. Tentacle-scales 2. 
D. Arms long, 7 to 12 times disk-diameter. 
E. Disk-spines rather blunt, not acicular, white, usually more or less clearly banded 
With dark! DrowMisj.cc <venle cioeriore sistas /e wie sia as iereie leo tyacsias oloewiaiste emcees annulosa 
EE. Disk spines very sharp, more or less acicular, unicolor and never banded. 
General coloration black and deep yellow; arm-spines black and not banded; oral 
shields with margins barely marked with yellow. ...............0.0e0e eee: janualis 
General coloration dark brown and whitish; arm-spines, at least proximally, more 
or less distinctly banded; oral shields with broad whitish margins.......... liitkent 
DD. Arms short, about 5 times disk-diameter. 
Upper arm-plates broadly fan-shaped, distal half and distal half of side arm-plates 
white or whitish; proximal halves very dark brown.............-....-+-++ caryophyllata 
Upper arm-plates broadly diamond-shaped (twice as wide as long) uniformly light 
gray or fawn color in marked contrast to dark side arm-plates.............. corallicola 
CC. Tentacle-scale single, except often on basal pores. 
D. Arm-spines commonly 4, sometimes 5, often only 3 on alternate segments. 
E. Claviform spines short and very stout; disk handsomely marked with irregular 
blackish lines \->- cst pgs Slay ce otro: SRSA, Bere era Sie ag eee venosa 
EE. Claviform spines slightly developed or wanting; disk not marked with black. 
Disk with conspicuous characteristic white markings; arms banded.......... variabilis 
Disk without markings and arms not banded ....................ceeeeecees ornata 
DD! -Arm-spinesyalternating/3:and) 242 noe acess eee ie eye ce ee eee bispinosa 
AA. Tentacle-scales wanting; no granules but some scattered spinelets on disk; arm-spines 3 and 2.. flaccida 
Ophiomastix asperula. 
Liitken. 1869. Add. ad Hist. Oph., pt. 3, p. 43—Déderlein. 1896. Jena. Denkschr., 8, pl. xv, figs. 9, 9a.— 
Koehler. 1905. Siboga Oph. Litt., pl. vi, figs. 11, 12. 
(Plate 14, Figure 1.) 
Although the colors are not bright, this is a very handsome brittle-star. It is quite 
Ophiocoma-like and may easily be confused with Ophiocoma wendtii at first glance. Indeed, 
the specimen in the Museum of Comparative Zoédlogy from Zanzibar, supposed to be an 
asperula (see H. L. Clark, 1915), proves, on critical examination, to be Ophiocoma wendti 
and not an Ophiomastix. It is in poor condition and for many years has borne the label 
