BARBADOS-ANTIGUA EXPEDITION 195 
the surface of the sand bottom or over and between rocks. It 
can also swim to a limited extent and will frequently raise it- 
self on end in the aquaria so as to assume a vertical position 
with the tentacles exploring the surface while the aboral end 
rests on the bottom. | 
This ereature has a peculiar sticky feel as if covered with 
an adhesive substance. This is due to the very remarkable and 
beautiful spicules found in enormous numbers embedded in the 
body walls. These are of three kinds:— First are the ‘‘an- 
chors,’’ beautiful representatives of the anchor of a ship, 
although quite minute, and looking as if made of glass. The 
general outline is perfect, except that the symmetrical hooks 
are devoid of flukes near their ends. The shank narrows grad- 
ually from the hooks to the basal end, which bears two opposite 
miniature hooks armed with a few nodules on their outer faces. 
The second kind of spicules is the ‘‘anchor plate.’’ These are 
flat plaques, oval in shape with one end suddenly narrowed into 
a smaller disk-shaped body. These plates are about two-thirds 
as long as the anchors. The main body is perforated by usually 
seven oval spaces, the inner edges of which bear fine denticles 
like the inside cogs of a wheel. The small disk-like extension at 
one side is like a very fine piece of fret-saw work, appearing to 
be very much more delicate in structure than the main body. 
When seen embedded in the integument, each anchor looks as if 
it were enclosed in a delicate sack and stands with the hooks up. 
Their very tips, however, appear to project from the investing 
sack, and doubtless it is these minute sharp points of the an- 
chors that give the adhesive feel to the integument of the live 
specimen, and the ‘‘sandy’’ feel to preserved ones. The end of 
the shank opposite the hooks is attached by what appears to be 
ligaments or muscles to the smaller disk-like ends of anchor 
plates, although the two sorts of spicules do not seem to be in 
aétual contact. The anchor plates are embedded more deeply in 
the integument than the anchors, and lie in a horizontal posi- 
tion, thus giving a very fine anchorage to the anchors themselves. 
The third sort of spicules is much smaller and in the ‘form 
of minute rosettes, being about half the diameter of one of the 
holes in the anchor plates. They are made up of very fine nod- 
ules of caleareous matter, looking like small lozenges encrusted 
