CLASS I ECHINOIDEA 257 



it is doubtful whether it may not be quite as properly assigned to oiie of 

 several other genera. Other Jurassic and Cretaceous forms have been 

 assigned by Lütken to Ophium Lamk. (Ophioglypha Lym.), and there is good 

 reason to believe that the genus, in a broad sense, is one of the oldest now 

 living. Fossil Ophiurans, whose disk-covering or mouth parts cannot be 

 determined, ought not to be assigned to Recent genera, but all such and all 

 others which cannot be accurately characterised may well be designated by 

 the broad term Ophiurites. 



[The text for the foregoiiig section on Asterozoa has been revised for the present work 

 by Dr. Hubert Lynian Clark, of the Harvard Museum of Comparative Zoology, at Cambridge, 



Massachusetts. — Editor. ] 



SuBPHYLüM C. Echinozoa Leuckart. 



Armless and non-pedunculate Echinodermata, with glohular, cordiform, discoidal 

 or worm-like bodies, which are either encased in a plated fest or are invested with a 

 leathery integument, emhedded within which are small-sized detached calcareous bodies. 



Olass 1. ECHINOIDEA Bronn. Sea-Urchin8.i 



Animals possessing a wide ränge of structure, but haxing alimentaiy, reproductive, 

 nerve and water vascular systeins within an enclosing superficial pentamerous plated 

 skeleton, which bears movable spines. There are front two to twenty columns of plates 

 in each of the five ambulacral areas, and from. one to fourteen columns of plates in 



1 Literature : Agassiz, L., and JJesor, E., Description des echinides fossiles de la Suisse, 1839- 

 1840. — Catalogue raisonne des familles, genres, et des especes de la classe des echinides. Aun. des 

 Sei. Nat., 1846-47. — cfOrUgny, A., Paläontologie fran^aise. Terrains cretacos 1853-55, vol. vi. — 

 Cotteau, G. H., and Triger, Echinides du departement de la Sarthe, 1857. — l)es(yr, E., Synopsis 

 des echinides fossiles. Paris, 1858. — Wright, T., Monograph on the British fossil Echinodermata 

 of the Oolitic Forniations. Palaeontograph. Soc, 1857-78.— /f^em, Cretaceous Formations. Palaeont. 

 Soc, 1864-82. — Cotteau, G., Paleontologie franfaise, vols. vii. , ix. and x., 1862-79. — Laube, G. C, 

 Echinodermen des vicentischen Tertiärgebietes. Denkschr. Akad. Wiss. Wien, vol. xxix., 1868. 

 — Loriol, F. de, and JJesor, E., Echinologie helvetique, vols. i.-iii. Geneva, lS%9i-%h.—Qnenstedt, 

 F. A., Petrefractenkunde Deutschlands (vol. iii., Echinideu), 1872-75. — Agassiz, A., Revision of 

 the Echiui. 111. Cat. Museum Comp. Zool. Cambridge, No. 7, 1872-74.— Reports on the Echini 

 of the Hassler (1874), Challenger (1881) and Blake (1883) Expeditions.— Z^^m, S., Etudes sur les 

 echinoidees. Svensk. Vetensk. Akad. Handl., vol. xi., 1874. — Cotteatc, Peron, and Gauthier, 

 Echinides fossiles de l'Algerie. Paris, 1876-91.— Loriol, P. de, Monographie paleontologique, etc. 

 Abhandl. Schweiz. Pal. Gesellsch., 1876-81, vols. iii., \m.— /James, W., Die Echiniden der 

 vicentischen und verouischen Tertiär-Ablagerungen. Palaeontographica, 1877, vol. xxv. — Agassiz, 

 A., Palaeontological and Embryological Development. Proc. Amer. Assoc. Adv. Sei., 1880. 

 —Duncan, P. M., and Sladen, W. P., Monograph of the fossil Echinoidea of Western Sind. 

 Palaeont. Indica, Ser. xiv., 1882-84:.— Schlüter, C, Die regulären Echiniden der norddeutschen 

 Kreide. Abhandl. zur geolog. Special-Karte von Preussen, vol. iv., 1883.— Jdem, Neue Folge, 

 Heft 5, 1892. — Loriol, P. de, Description des echinides. Commission des travaux gcol. du Portugal, 

 1887-88, vol. iu—Loveu, S., On Pourtalesia. Svensk. Vetensk. Akad. Handl., 1884, vol. xix.— 

 Pomel, jV. A., Classification mcthodique et genera des echinides Vivantes et fossiles, 1883.— Duncan, 

 P. M., Revision of the Genera and Great Groups of the Echinoidea. Joum. Liun. Soc, 1889, 

 vol. yix\\\.—Loven, S., Echinologica. Bihang tili Svensk. Vetensk. Akad. Handl., 1892, vol. 

 xvm.— Clark, W. B., Mesozoic Echinodermata of the United States. Bull. U.S. Geol. Survey, 



No. 97, 1893. Tornqnist, A., Das fossil führende Untercarbon am östlichen Rossbergmassiv 



in den Südvogesen, iii., Beschreibung der Echiniden- Fauna. Abhandl. Geol. Special-Karte Elsass- 

 Lothringen, 1897, vol. v. — Mortensen, T., Slam Echinoidea. Danske Vidensk. Selsk. Skrift., 

 1904, vol. i. — Bather, F. A., Triassic Echinoderms of Bakony. Resultate der wiss. Erforsch. Bala- 

 tonsees, 1909, vol. l— Lambert, J. and ThiSry, P., Essai de nonienclature raisonne des echinides. 

 Chaumont, 1%Q9-Vl.-J<'cksnn, R. T., Phylogeny of the Echini. Mein. Boslon S,.r. Xat. llist., 

 1912, vol. wn.—IL'wkliis, II. />., Chissification of tlie Holectyponla. itc 1»i.m-. /,„,!. >,„•. 

 London, 1912. 



VOL. I ^ 



