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. Animal studies. 152 ANIMAL STUDIES skeleton indicate that the sea-urchin is comparable to a starfish, with its dorsal surface reduced to insignificant proportions. In the sea-urchins the calcareous plates possess a great regularity, and are so closely interlocked that they prevent. Fig. 91.—Brittle- or serpent-stars (species undetermined). Natural size. any motion of the body-wall. Also, each plate is usually provided with highly developed spines, movable upon a ball- and-socket joint. These spines serve for locomotion, and, in some instances, for conveying food to the mouth. A considerable
. Animal studies. 152 ANIMAL STUDIES skeleton indicate that the sea-urchin is comparable to a starfish, with its dorsal surface reduced to insignificant proportions. In the sea-urchins the calcareous plates possess a great regularity, and are so closely interlocked that they prevent. Fig. 91.—Brittle- or serpent-stars (species undetermined). Natural size. any motion of the body-wall. Also, each plate is usually provided with highly developed spines, movable upon a ball- and-socket joint. These spines serve for locomotion, and, in some instances, for conveying food to the mouth. A considerable number of sea-urchins show an irregularity in form which destroys to a corresponding degree the radial symmetry. This is due to various causes, but especially to a compression of the body, which, in the " sand-dollars,''. 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 Jordan, David Starr, 1851-1931; Kellogg, Vernon L. [from old catalog].
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Keywords: ., bookauthorjordanda, bookcentury1900, bookdecade1900, bookyear1903