Distribution of Inttoral Echinoderms of the West Indies. 57 
Ophiactis cyanosticta H. L. Clark. Ophiopsila riisei Liitken. 
lymani Ljungman. vittata H. L. Clark. 
savignyl (Miller & Tros- | Ophioderma appressum (Say). 
chel). brevicaudum Liitken. 
Ophiothrix angulata (Say). brevispinum (Say). 
brachyactis H. L. Clark. cinereum Miiller & Tros- 
lineata Lyman. chel. 
cerstedii Liitken. guttatum Liitken. 
suensonii Liitken. januari Liitken. 
Ophionereis olivacea H. L. Clark. phoeenium H. L. Clark. 
reticulata (Say). rubicundum Liitken. 
squamulosa Koehler. squamosissimum Liitken. 
Ophiocoma echinata (Lamarck). Ophiozona impressa Liitken. 
pumila Liitken. Ophiolepis elegans Liitken. 
riisei Liitken. paucispina (Say). 
While certain of the above species are subject to great diversity, 
especially in color, it is fortunately true that nearly all, even in such 
genera as Amphiura and Ophiothrix, are recognizable with compara- 
tively little difficulty. Specific limits in the genus Ophiactis are not 
very well defined; in particular, the species miillert and savignyi have 
been much confused and young individuals are certainly hard to 
separate. Adult miilleri seems, however, to be a much larger and 
darker-colored animal than adult savignyi and, so far as I can learn, 
it inhabits deeper water and does not occur on the reefs accessible at 
low tide. It is therefore ignored in this list. The genus Ophiothrix 
contains the most ill-digested assemblage of species of any genus of 
ophiurans, but the littoral West Indian species are not hard to separate 
when once their distinctive characters are understood. The extra- 
ordinary diversity of color and disk spinulation shown by O. angulata 
is certainly perplexing but each of the other species has distinguishing 
characters which are quite easy to see at once. In the genus Ophio- 
derma, the species appressum and brevispinum are so similar that they 
are often confused. Typical examples are not difficult to distinguish, 
but each form is variable and some of the varieties are not readily 
assigned. Consequently, the records of these common and long- 
known species are not wholly reliable and the exact limits of their 
relative distributions is still uncertain. 
Before separating the West Indian brittle-stars into the half-dozen 
groups into which the sea-stars were divided, we must eliminate the 
following 14 species, which are known from only a single locality and 
not infrequently from only a single specimen. 
Ophiacantha oligacantha. Amphiodia tymbara. 
Ophiomitrella glabra. Amphioplus coniortodes. 
Ophiophragmus filograneus. thrombodes. 
pulcher. Ophiactis cyanosticta. 
Amphipholis pachybactra. Ophiopsila vittata. 
Amphiodia rhabdota. Ophioderma phoenium. 
trychna. squamosissimum. 
