14 ECHINODERMATA—PELMATOZOA SUB-KINGDOM IIT 
type from which both the Blastoids and Crinoids have been derived, neverthe- 
less, it is expedient to treat of the Crinoids first, since a knowledge of the 
anatomy in recent forms is essential to an adequate conception of the extinct. 
Class 1. CRINOIDEA, Miller. Sea-lilies.! 
(Brachiata, Bronn ; Actinoidea, F. Roemer.) 
Usually long-stalked, more rarely non-pedunculate and sessile, occasionally free- 
swimming Pelmatozoa with calyx composed of regularly arranged plates, and provided 
with well-developed movable arms. 
The Crinoid organism consists of three principal elements—calyx, arms, 
and stalk. The calyx and arms together are sometimes spoken of as the 
crown, as contrasted with the peduncle. 
1. The Calyx.—The calyx has usually the form of a cup-, bowl-shaped, or 
globular capsule, within which the more important organs are enclosed. — Its 
lower (dorsal or abactinal) surface commonly rests upon a peduncle (Fig. 219) ; 
but in some forms it is attached directly by the base, and in rare instances it is 
tree. The superior (ventral or actinal) surface is either membraneous or plated ; 
it carries the mouth and ambulacral grooves, and hence is homologous with the 
under side of a star-fish or sea-urchin. As a rule, only the inferior and lateral 
portions (dorsal cup) of the calyx are visible, owing to the concealment of the 
summit by the arms. The cup is constituted of two or more circlets of plates, 
which are uniformly oriented with reference to the ambulacral organs. 
By the base is understood the one or two rings of plates intervening 
between the topmost joint of the column and the first cycle of plates situated 
in the projection of the ambulacra or arms. When the basis is monocyclic 
(Fig. 220) the position of the proximal ring of plates is interradial ; but when 
dicyclic it is radial, and the upper ring corresponds with the basals of mono- 
cyclic forms. 
In the nomenclature of P. Herbert Carpenter, the upper series of plates in 
1 Literature : 
Miller, J. S., A Natural History of the Crinoidea or lily-shaped Animals. 1821. 
Miiller, J.,Ueber den Bau des Pentacrinus caput medusae (Abhandl. Berliner: Akad.), 1841. 
de Koninck, L. G., et le Hon. H., Recherches sur les Crinoides du terrain carbonifére de la Belgique. 
Brussels, 1854. (Very extensive bibliography. ) 
Beyrich, E., Die Crinoideen des Muschelkalks (Abhandl. Berliner Akad.), 1857. 
Schultze, L., Monographie der Echinodermen des Hifler Kalks (Denkschrift der k. k. Akad. der 
Wissenschaften), Vienna, 1866. 
Shumard, B. F., Catalogue of Palaeozoic Echinodermata of North America (Trans. St. Louis Acad. 
Sci. vol. II.), 1868. (Very complete bibliography.) 
Carpenter, W. B., On the Structure, Physiology, and Development of Antedon rosaceus (Philo- 
sophical Transactions Royal Society, vol. CLVI.), 1876. 
Wachsmuth, C., and Springer, I., Revision of the Palaeocrinoidea. I.—III. (Proe. Acad. Nat. Sci. 
Philad.), 1879-86. 
Wachsmuth, C., and Springer, F., Discovery of the Ventral Structure of Zaxocrinus and Huplocrinus, 
ibid., ee 
W Tachsmuth, 1, and Springer, 4 , The Perisomic Plates of Crinoids, ibid., 1890. 
Wace hsmuth, 0 , and Springer, F., "The Crinoidea Camerata of North America. (In preparation.) 
Loriol, P. de, Paléontologie Rance Crinoides Jurassiques, I.—II., 1882-89. 
Neumayr, M., Die Sttimme des Thierreichs. Band I., 1889. 
Agassiz, A., Calamocrinus Diomedae (Memoirs Museum Comp. Zool. vol. XVII.), 1892. 
Bather, F. A., British Fossil Crinoids (Ann. and Mag. Nat. Hist. (6th ser.), vols. V.—VII.), 1890-92. 
Bather, F’. A., The Crinoidea of Gotland (K. Svenska. Vetensk. Akad. Handlingar, vol. XXY.), 1892. 
