210 ECHINODERMATA—ECHINOZOA SUB-BRANCH III 
Order 2. CRYPTOZONIA. Sladen. 
Marginal plates inconspicuous and more or less rudimentary in the adult. 
Supero-marginal plates often separated from the infero-marginal series by inter- 
mediate plates. Papulae distributed over the whole body. Ambulacral plates 
crowded and narrow ; tube feet in two or four rows. 
Of the Palaeozoic representatives of this order, the genera Lepidaster, 
Forbes (Silurian), and Loemeraster, Stiirtz (Devonian), are related to the 
recent genus Linckia, Nardo. The forms described by Stiirtz, Echinasterella, 
Medusaster, and Protasteracanthion, from the Deyonian of Bundenbach, are 
regarded by their author as allied to the Hchinasteridae, Asteriidae, and 
Brisingidae respectively. 
Solaster, Forbes, is represented by a form having numerous arms in the 
Great Oolite of England. Tvropidaster, Forbes, occurs in the Middle Lias ; 
and a solitary species of Echinaster, M. and T. (hopia, Gray), has been 
described from the Neocomian. A form described by Forbes from the Red 
Crag of England was considered by him to be specifically identical with the 
existing Asterias rubens, Linné.! 
Sup-Brancu III. Echinozoa. Leuckart. 
Armless and stemless Echinodermata, with globular, cordiform, discoidal, or 
worm-like bodies, which are either encased in a plated test or are covered with a 
leathery skin, in which minute, detached calcareous bodies are embedded. 
The Echinozoa are divided into two classes: Echinoidea or Sea-urchins, and 
FHolothurioidea or Sea-cucumbers. 
Class 1. ECHINOIDEA. Agassiz. Sea-Urchins 
Echinozoa, with bodies encased in a solid or slightly flexible test, variable in shape 
from spherical to flat ; composed of numerous, closely placed, more or less geometrical 
1 [To Mr. W. Perey Sladen, Vice-President of the Linnean Society, and well known for his 
numerous scientific achievements, the author and editor are under special obligations for having 
thoroughly revised and enlarged the preceding chapter on the Asterozod, and also for having 
rendered valuable assistance on the Hchinozoa.—TRANs. } 
2 Agassiz, L., and Desor, E., Description des Echinides fossiles de la Suisse, 1839-40.—Catalogue 
Raisonné des Familles, Genres, et des Especes de la Classe des Bchinides (Ann. des. Sci. Nat.), 
1846-47.—d’ Orbigny, A., Paléontologie francaise (Terrain crétace, vol. VI.), 1853-60.—Cotteaw and 
Triger, ichinides du departement de la Sarthe, 1855-69. —Desor, E., Synopsis des Echinides fossiles. 
Paris, 1858.— Wright, 7., Monograph on the British fossil Echinodermata of the Oolitic Formations 
(Palaeontograph. Soc.), 1857-80.—Jdem, Cretaceous Formations (Palaeont. Soc.), 1864-82.— 
Cotteau, G., Paléontologie francaise, vols. VII., IX., and X., 1862-79.—Laube, G. C., Echinoder- 
men des vicentischen Tertiiirgebietes (Denkschr. Wien. Akad. xxix.), 1868.—de Loriol. P., 
Hehinologie helvétique, vols, I.-III. Geneva, 1868-75.—Quenstedt, F. A., Petrefactenkunde 
Deutschlands (Bd. IIJ., Echiniden), 1872-75.— Agassiz, A., Revision of the Echini (Ill. Cat. 
Museum Comp. Zool. Cambridge, No. 7), 1872-74.—Reports on the Echini of the Hassler (1874), 
Challenger (1881) and Blake (1883) Expeditions.—Lovén, S., Etudes sur les Echinoidées (Svensk. 
Vetensk. Akad. Handl., Bd. XI.), 1874.—Cotteau, Peron, and Gauthier, Kchinides fossiles de 
Algérie. Paris, 1876-91.—de Loriol, P., Monographie paléontologique, ete. (Abhandl. Schweiz. 
pal. Gesellsch, III.-VIII.), 1876-81.—Dames, W., Die Echiniden der vicentischen und veronischen 
Tertiiir-Ablagerungen (Palaeontographica, Bd. XXV.), 1877.—Agassiz, A., Palaeontological and 
Embryological Development (Address before Amer, Assoc. Ady. Science), 1880,— Bibliography of 
the Echinodermata (Bull. Museum Comp. Zool. Cambridge, vol. X., No. 2), 1882.—Duncan, P. M., 
and Sladen, W. P., Monograph of the fossil Echinoidea of Western Sind (Palaeont. Indica, Ser. 

