. Ocean wonders: a companion for the seaside. z, in her Sea-sideStudies, says that this flatvariety of the echinoids be-longs to the family knownas the shield-like sea-urchin(clypeastroids). When speak-ing of the teeth of the JEchi-noder?nata, we should have mentioned that they have a concentric motion—all converg-ing toward the centre, never moving up and down as with■vertebrate animals. These sand-cakes are found all along theMassachusetts shore, but do not extend to Long Island Soundor New York Bay. Ojphiurans are related to the star-fish, and their rays orarms are iive in number, like the
. Ocean wonders: a companion for the seaside. z, in her Sea-sideStudies, says that this flatvariety of the echinoids be-longs to the family knownas the shield-like sea-urchin(clypeastroids). When speak-ing of the teeth of the JEchi-noder?nata, we should have mentioned that they have a concentric motion—all converg-ing toward the centre, never moving up and down as with■vertebrate animals. These sand-cakes are found all along theMassachusetts shore, but do not extend to Long Island Soundor New York Bay. Ojphiurans are related to the star-fish, and their rays orarms are iive in number, like the common variety, Urasterrubens, but totally unlike in general appearance. In the com-mon five-fingered stars,the broad bases of therays form the central bodyof the animal; but withthe ophiurans the armsare long and slender,nearly cylindrical in form,being slightly narrowedtoward the extremities;they appear to be attachedto, rather than to be grow-ing out of, the small disk-like body. The SpinOUS Sebpent, ok Beittle Stae-Fish (Ophiopolis).. 146 THE OCEAN. projections, which fringe the edges of these long arms, sug-gest the idea of five centipedes placed at regular intervalsaround the disk, and wriggling about with the intention oftwisting themselves off if they can; and indeed they oftendo succeed, or rather the creature throws them off if muchfrightened, or, to escape capture, it will sacrifice one to savethe rest. Like some others of this class, it has suicidal ten-dencies. It is a very free swimmer, its centipedal armsforming excellent oars. Their mode of progression on the shore or over rocks islike that of the common star, by putting forward one armfirst, and then drawing the others after it. Their tentaclesdo not terminate with a sucking-disk, as in the star-fishes andurchins, but are covered with small tubercles. Neither havethey teeth like the sea-urchin, but as a substitute they areprovided with a bony plate at that end of the ambulacra con-necting with the oral orif
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectmarineanimals, bookye
