Elementary text-book of zoology, general part and special part: protozoa to insecta . elementarytextbo00clau Year: 1892 296 ECHINODEH M ATA, lacral branchite upon a rosette formed of large pores on the dorsal sui'face (fig. 239). The locomotive feet are very small in Chjiyeastridce, and are distributed either over the whole surface of the ambulacra, or are confined to branching rows upon the ventral sui^face. In the SpataiifjicUe there are peculiar bands upon the upper surface, the fascioles or semitce (fig. 239), upon which, in place of the spicules, knobbed bristles with active cilia [clavu
Elementary text-book of zoology, general part and special part: protozoa to insecta . elementarytextbo00clau Year: 1892 296 ECHINODEH M ATA, lacral branchite upon a rosette formed of large pores on the dorsal sui'face (fig. 239). The locomotive feet are very small in Chjiyeastridce, and are distributed either over the whole surface of the ambulacra, or are confined to branching rows upon the ventral sui^face. In the SpataiifjicUe there are peculiar bands upon the upper surface, the fascioles or semitce (fig. 239), upon which, in place of the spicules, knobbed bristles with active cilia [clavuke) are distributed. Develop- ment takes place with a Pluteus larval stage, in which the larva is pro\'ided Avith ciliated epaulettes or with an apical rod. The Sea-urchins live, as a rule, near the coast, and feed on molluscs, small marine animals, and Fuci. Some species of Echinus have the power of boring holes in the rocks in which they live. We find many fossil shells, especially in the chalk. Fig. iZ^.—Brlssopsie lynfera with the fascioles or Semites surround- ing the rosette. A, anus. Order 1.—Cidaeidea=Regular Sea-uechixs. Echinoidea with central mouth and egual hand-like amhvlacra; with teeth and masticatory apparatus ; with suh-central anus in the apical space. Farn. Cidaridse. 'SVith very narrow ambulacral and broad interambulacral areas, on both of which are large perforated tubercles and club-shaped spines. There are no oral branchije. Cidaris mctularia Lam., Phyllacantlms imxjerialis Lam., East Indies. Fam. Echinidae, Sea-urchins. The pores are grouped in transverse rows ; there is a round, thin shell, broad ambulacral spaces bearing tubercles and spines, which are mostly short and pear-shaped. Oral branchias are present. To-voj)- nciistcK variefjatu-t, Lam., Ecldmis melo Lam., Strongylocentrotus Uvidus Brit. Lin., Mediterranean. Fam. Echinometridae. AVith long oval shell, imperforate tubercles and oral branchia\ Eclilni'mctva olloiiga Blainv., Po
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