OPHIURID.^. 



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 Asterophyion verrn- 

 costim, which is represented in Fig. no, is yellowish ; its disc about 

 four inches, its arms sixteen to eighteen ; it inhabits the Indian 

 Ocean. Another species, A. arborescens, is met with on the coasts 

 of Sicily and other parts of the Mediterranean. Nothing can be 



Fig. III. — Acrocladia mamillata (Lamarck), natural size. 



more elegant than these animated discs, which resemble nothing so 

 much as a delicate piece of lace — a piece of living lace moving in 

 delicate festoons in the bosom of the ocean. 



ECHINID^. 



The'singular shape of the Echinidse, or Sea-urchins (Plate VIII.), 

 and the spiny armature with which their bodies are covered, has in all 

 ages attracted the attention of naturalists. Aristotle applied to them 

 liie name iy^lvos, 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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