AMERICAN DREDGINGS IN THE CARIBBEAN SEA. 
359 
tion ; although, of course, on the look-out for black Holopus, I 
did not notice this imperfect whitish specimen, which must have 
been alive, among the numerous Pentacrini with which it came 
up. Our collection of Pentacrini is quite extensive ; we found them 
at Montserrat, St. Vincent, Grenada, Gruadeloupe, and Barbadoes, 
in several places, in such numbers that on one occasion we 
brought up no less than 1 24 at a single haul of the bar and tangles. 
We must, of course, have swept over actual forests of Pentacrini 
crowded together much as we find the fossil Pentacrini on slabs. 
Our series is now sufficiently extensive to settle satisfactorily the 
number of species of the genus found in the West Indies. There are 
undoubtedly the two species which have thus far been recognized. 
It is evident that they vary greatly in appearance, P. Miilleri 
being the most variable. I have nothing to add to the general 
description of their movements given by Captain Sigsbee in 
my second letter, with the exception of their use of the cirri 
placed along the stem. These they move more rapidly than the 
arms, and use them as hooks to catch hold of neighbouring 
objects, and, on account of their sharp extremities, they are 
well adapted to retain their hold. The stem itself passes slowly 
from a rigid vertical attitude to a curved or even drooping posi- 
tion. We did not bring up a single specimen showing the 
mode of attachment of the stem. Several naturalists, on the 
evidence of large slabs containing fossil Pentacrini, where no 
basal attachment could be seen, have come to the conclusion 
that Pentacrini might be free, attaching themselves temporarily 
by. the cirri of the stem, much as Comatulse do. I am in- 
formed, however, by Captain E. Cole, of the telegraph steamer 
Investigator , that he has frequently brought up the West India 
telegraph cable on which Pentacrini were attached, and that 
they are fixed, the basal extremity of the stem spreading slightly, 
somewhat after the manner of Holopus, so that it requires con- 
siderable strength to detach them. 
The collection of Ophiurans is perhaps the largest ever made. 
They seem to play a very important part in determining the 
facies of a fauna. They occur everywhere, at all depths, and 
often in countless numbers. I hardly think we made a single 
haul which did not contain an Ophiuran. They often came up 
when the trawl brought nothing else. In some places the bottom 
must have been paved with them, just as the shallows are some- 
times paved with Starfishes and Echini, and many species 
hitherto considered as extremely rare are found to be really 
abundant. Most, or perhaps all, the deep sea Atlantic species 
obtained by the Challenger have been re-discovered in large 
numbers. Such rare species as Sigsbeia murrhina , Ophiozona 
nivea , Hemieuryale pustulata , and Ophiocanax hystrix , were 
found in plenty. Among the representatives of northern seas 
