. Fourteen weeks in zoology. Zoology. IV. SUBKINGDOM ECHINODER- MATA. General Characteristics.—The Eohinoderms (spiny- skinned) have all the parts symmetrically arranged around a central axis, thus necessitating a peculiar system of radiating canals and nervous ganglia. They are all ovipa- rous. They respire by a water-vasculary system permeating the entire body. There is also a blood vascular system, with a central contractile heart. 'Body cylindrical ; free ; mouth forward. Holothuroide^ »-^i iLiy-vrM-ntj .* BODT SPHERICALORPLAT; FREE; MOUTH UNDERNEATH. Echinoide». „ Body
. Fourteen weeks in zoology. Zoology. IV. SUBKINGDOM ECHINODER- MATA. General Characteristics.—The Eohinoderms (spiny- skinned) have all the parts symmetrically arranged around a central axis, thus necessitating a peculiar system of radiating canals and nervous ganglia. They are all ovipa- rous. They respire by a water-vasculary system permeating the entire body. There is also a blood vascular system, with a central contractile heart. 'Body cylindrical ; free ; mouth forward. Holothuroide^ »-^i iLiy-vrM-ntj .* BODT SPHERICALORPLAT; FREE; MOUTH UNDERNEATH. Echinoide». „ Body STAR-SHAPED ; free; mouth underneath. Asteroidea. .Body CUP-SHAPED ; fixed ; mouth uppermost. GrinoidefL CLASS I. HOLOTHURQIDEA. General Characteristics.—The Holothuroids (whole- mouthed) have a tough skin, sprinkled with calcareous granules. The mouth is surrounded with feathery tentacles, Mg. IM. ^t. Pentactafi'ondSsa, Holothuroid or Sea-cucumljer. and the body is worm-shaped, though constructed upon the radiate plan. By means of their powerful longitudinal and transverse muscles, they can disgorge their own stomachs, and even throw of£ their tentacles, and, after remaining inert for a season, take on a new set of the rejected Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Steele, Joel Dorman, 1836-1886. New York, Chicago [etc. ] A. S. Barnes & Company
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectzoology, bookyear1872
