Crossword-Solution: ECHINODERM 10 letters, 4 clues 🏆 scrabble score: 18

See Bivious.] (Zo”l.) One side of an echinoderm, including a pair of ambulacra, in distinction from the opposite side (trivium), which includes three ambulacra.

Each of these anchors is jointed at its root into one end of a curious cribriform plate,—in plain English, one pierced like a sieve, which lies under the skin, and reminds one of the similar plates in the skin of the White Cucumaria, which I will show you presently; and both of these we must regard as the first rudiments of an Echinoderm’s outside skeleton, such as in the Sea-urchins covers the whole body of the animal.

There is no more difficulty in understanding how the branched spines of some ancient Echinoderm, which served as a defence, became developed through natural selection into tridactyle pedicellariæ, than in understanding the development of the pincers of crustaceans, through slight, serviceable modifications in the ultimate and penultimate segments of a limb, which was at first used solely for locomotion.

Having thus endeavored to sketch each different kind of Echinoderm, let us try to forget them all in their individuality, and think only of the structural formula that applies equally to each.

Among Radiates, the Corals were more nearly allied to those of the earlier ages than to those of modern times, and Crinoids abounded still, though some of the higher Echinoderm types were already introduced.