BARBADOS-ANTIGUA HXPHDITION 193 
or conjunction of characters has determined the success of this, 
as well as of many other species of Echinoderms, e. g. Diadema 
antiliarum. 
Ophiocoma riisei 1s a species that greatly resembles the last, 
O. echinata, and is found associated with it although not nearly 
so abundant. It differs from 0. echinaia in having one tentacle- 
seale instead of two and having the upper arm-spine much 
longer than the others. Another Ophiocoma has greenish yel- 
low arms banded with brown. it was abundant in the same re- 
gion with the others, but seems quite a distinct form. Ophio- 
nerers reticulaia has the disk marked with an open reticulation 
of reddish brown lines, three arm-spines, and supplementary 
arm-plates. It bears a very close superficial resemblance to*the 
Ophiocoma just mentioned, so close that it looks like a case of 
camouflage. The genus Ophiolepis is represented by a species 
with the disk covered with rounded seales surrounded by smaller 
ones. The side mouth-shields are very large and almost touch each 
other. There are many representatives of Ophiura greatly dif- 
fering in color, but all having the four genital slits character- 
istic of the genus. Many are doubtless the familiar O. cinerea. 
One form is very dark olivaceous green, almost black, while 
some young specimens have very distinct but distant arm-bands 
of dark greenish. A single specimen of Ophiomyxa flaccida 
was secured. 
_ Holothurians—Dr. Fisher found a number of species of this 
sroup and will officially report on them. He has kindly given 
me the names of those mentioned below and also some comments 
which i incorporate. 
Stichopus mobi is a large heavy species often reddish brown 
and with an exceedingly tough integument. I understand that 
this is the form commercially known, when dried, as ‘‘trepang’’ 
im Oriental countries. It is quite abundant in English Harbor 
and Falmouth Harbor. Dr. Fisher said that he found this the 
most difficult to kill extended of all the holothurians collected, 
‘‘as the mechanical contraction of the heavily muscled body 
wall would foree out the viscera even after the creature was 
apparently dead.’’ He also says that these heavily muscled or 
thick-walled holothurians ‘‘are the ones most given to dispensing 
