. A manual of zoology. Zoology. Fig. 292.—Ophiopholis aculeala''' (from Morse). Fig. 293.—AstropJiyton arborescens, basket fish (frotn Ludwig). Class III. Crinoidea (Pelmatozoa). The crinoids or sea lilies are on the road to extinction. In early times, especially in the paleozoic, they were very abundant, but to-day there are but few species, these mostly restricted to the greater depths of the ocean, only the Comatulidas occurring near the shore. The crinoids are attached to the sea bottom by a long stalk (fig. 294), composed of cylindrical discs which often bear five rows of outgrowths, the
. A manual of zoology. Zoology. Fig. 292.—Ophiopholis aculeala''' (from Morse). Fig. 293.—AstropJiyton arborescens, basket fish (frotn Ludwig). Class III. Crinoidea (Pelmatozoa). The crinoids or sea lilies are on the road to extinction. In early times, especially in the paleozoic, they were very abundant, but to-day there are but few species, these mostly restricted to the greater depths of the ocean, only the Comatulidas occurring near the shore. The crinoids are attached to the sea bottom by a long stalk (fig. 294), composed of cylindrical discs which often bear five rows of outgrowths, the cirri. The young Coma- tulidffi (fig. 295) are similarly attached, having a Pentacrinus stage, but later they separate and live a free life, a proof that the attached condition was primitive. When the separation takes place, one joint of the stalk. 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 Hertwig, Richard, 1850-1937; Kingsley, J. S. (John Sterling), 1854-1929, ed. and tr. New York, H. Holt
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectzoology, bookyear1912
