Elementary text-book of zoology, general part and special part: protozoa to insecta . elementarytextbo00clau Year: 1892 STELLEBIDEA. 293 situate inter-radially and upon the dorsal surface. The multilobed branched diverticula of the stomach extend into the cavities of the arms (fig. 218). On the ventral surface of the latter, two or four rows of ambulacral feet project from the deep ambulacral groove, the edge of which is beset with papillse (fig. 235). Pedicellarice are also found, and dermal gills projecting through the tentacular pores of the dorsal surface. They feed principally upon Mollu
Elementary text-book of zoology, general part and special part: protozoa to insecta . elementarytextbo00clau Year: 1892 STELLEBIDEA. 293 situate inter-radially and upon the dorsal surface. The multilobed branched diverticula of the stomach extend into the cavities of the arms (fig. 218). On the ventral surface of the latter, two or four rows of ambulacral feet project from the deep ambulacral groove, the edge of which is beset with papillse (fig. 235). Pedicellarice are also found, and dermal gills projecting through the tentacular pores of the dorsal surface. They feed principally upon Mollusca, and, by means of their ambulacral feet, ci-awl slowly upon the bottom of the sea. Some few of them are developed by a very simple process of metamorphosis within the brood-pouch of the mother; but the greater number of them pass through the free larval stages of Jjipinnaria and Brachiolaria (figs. 22-i and 228), Fam. Asteriadae. The cylin- drical ambulacral feet end in broad suctorial discs, and are usually arranged in four rows along each ambulacral groove. L. (^Asteracanthion'), A. rjlacialis 0. F. Mliller., Hi- Uastcr lii-Viantlnis Gray. Fam. Solasteridae. The cylin- drical ambulocral feet are dis- posed in two rows. Eays long, often more than five Solastcr jyaijposnis Retz., Ecli'master seposltns Eetz., Opkkliaster Ag., Llnckia Nardo. Fam. Astropectinidae. Am- bulacral feet conical, and with- out suctorial disc, arranged in two rows. There auranticicus Thil. Lnidia Forb., Ctcnodiscns Mlill. Tr. Fam. Brisingidae. Body shaped like an Ophiurid. Eays distinct from the disc with only a narrow internal cavity. Brisinga coronata Sars. Sub-Class 2.—Ophiuridea {Brittle Stars). Asteroidea characterised hy the absence of an amis, and by the pos- session of long cylindrical arms which are sharjyly distinct from the disc, and do not contain c^ppendages of the alimentary canal. The ambulacral groove is covered by the dermal p)lates so that the ambulacral feet p)i'oject a
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