. Zoology for high schools and colleges. Zoology. Fig. 69.— Oan/ocys- iites, a CyBtidean.— After Fig. 71.—Agelacrinus, a Cystidean, ou the Bnell of aBrachiopod.—After Lutkeu Pig. 70.—Pseudocri- nus^ a Cystidean.— After Liitken. body being angulo-spherical, composed of solid plates. The Cystideans (Figs. 69 to 71) originated in the Cambrian for- mation, attained their maximum development in a number of species in the Silurian, and became mostly extinct in the Carboniferous period. Class I.—CRINOIDEA. Spherical or cup-shaped Echvrwderms, wiCnout a madreporic plate, vxu- ally attached b
. Zoology for high schools and colleges. Zoology. Fig. 69.— Oan/ocys- iites, a CyBtidean.— After Fig. 71.—Agelacrinus, a Cystidean, ou the Bnell of aBrachiopod.—After Lutkeu Pig. 70.—Pseudocri- nus^ a Cystidean.— After Liitken. body being angulo-spherical, composed of solid plates. The Cystideans (Figs. 69 to 71) originated in the Cambrian for- mation, attained their maximum development in a number of species in the Silurian, and became mostly extinct in the Carboniferous period. Class I.—CRINOIDEA. Spherical or cup-shaped Echvrwderms, wiCnout a madreporic plate, vxu- ally attached by a jointed stem, a few free in adult life, with Jim arms sub- diwding into pinnuke; the atniulacrai feet in the form of tentacles arising around the mouth in the furrows of the calyx or situated on the jointed a/rms. In the Blastoidea and certain Cystideans the arms are ab- sent, but the pinnulm are usually present, though absent in Caryocystites. Circulatory, water-vascular, and sexual organs much as in othei' Echini dermis ; tlie digestive canal ending in a disUnet eccentric 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 Packard, A. S. (Alpheus Spring), 1839-1905. New York, H. Holt and Company
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Keywords: ., bookcentury1800, bookdecade1880, bookpublishe, booksubjectzoology
