BEFORE THE DAWN OF ART 283 
burrowing worms, for long sponge-spicules radiate 
out in all directions, forming an effective chevaux de 
frise either at the mouth of the shell or all over the 
body of the builder. 
Another extraordinary instance of unconscious 
skill is to be found in the shell of a species of Psam- 
mosphzra dredged by Mr. Earland on the Gold- 
seeker in the North Sea in happier days than these 
(1915). This creature, which lives on very muddy 
parts of the sea-floor, uses long sponge-spicules 
(2-3 mm. in length) to form the foundation-poles 
of an open framework or chamber. “The open 
spaces in the wall are then filled in with fragments 
. of spicules carefully selected for length so as exactly 
to fill the spaces that are to form the walls of the 
test, an awkward triangular terminal space being 
frequently filled in with a truncated triaxial spicule.” 
The creature lives in its roughly spherical house, and 
the projecting ends of the long spicules serve as 
“catamaran spars’’ to support the whole on the 
surface layer of the ooze. And the wonder of adap- 
tation does not end here, for we read that a second 
and often a third individual will in the building 
of its house make use of the extreme ends of long 
spicules which project from its neighbor’s construc- 
tion. Two or three individuals united in this way 
by their “ catamaran spars” remain entirely distinct 
organisms, “ their only connection with one another 
being a purely utilitarian one, the association 
offering greater resistance to the mud than a single 
individual can attain.” It is, as Mr. Heron-Allen 
