OPHIURIDA, 275 
at the same time they constitute a series of living thread-like weapons 
which seem intended to seize and close upon the animals which 
serve as prey to these little flesh-eaters. The Asterophyton verru- 
cosum, which is represented in Fig. 110, is yellowish ; its disc about 
four inches, its arms sixteen to eighteen; it inhabits the Indian 
Ocean. Another species, 4. arborescens, is met with on the coasts 
of Sicily and other parts of the Mediterranean. Nothing can be 
Fig. 131.—Acrocladia mamillata (Lamarck), natural size. 
more elegant than these animated discs, which resemble nothing so 
much asa delicate piece of lace—a piece of living lace moving in 
delicate festoons in the bosom of the ocean. 
EcCHINIDA. 
The singular shape of the Echinidz, or Sea-urchins (PLavE VIII.), 
and the spiny armature with which their bodies are covered, has in all 
ages attracted the attention of naturalists. Aristotle applied to them 
the name éxives, which signifies urchin. When, however, one sees the 
body of one of these animals thrown on the sea-shore, it is difficult, 
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