CLASS IV. 
ECHINODERMS (Z£CHINODERMATA)'. 
THE name Echinodermata was used by J. T. KLEIN rather 
more than a century ago, to denote the shells of the sea-urchins, 
called Echind. ’Eyivos, with the Greeks, denoted both an urchin 
and a sea-urchin. Afterwards BruGuIERES gave the name of 
Echinodermata to a division of the animal kingdom that comprised 
at once the sea-urchins and the star-fishes. Cuvirr retained that 
name for this division, but added to it animals having a coriaceous 
skin without spines or quills. Although the name is no longer 
applicable to all the species of this class, yet the class itself must 
be looked upon as an extremely natural division of the Animal 
Kingdom. ‘These animals are distinguished by an intestinal canal 
hanging free in the cavity of the body by single threads or mem- 
branes, usually long and tortuous, or provided with lateral append- 
ages if it be short: blood vessels and respiratory organs are present; 
the genital organs, in both sexes of the same external form, are 
without any special apparatus for copulation ; the fertilisation being 
1 Consult on this class : 
L. Acassiz, Monographies d’ Echinodermes vivans et fossiles. Neuchcatel, 1838 and 
fols. 4to. (The parts thus far have reference only to certain figures of Echini. The 
fourth, published in 1842, contains the anatomical description of Echinus lividus, by 
VALENTIN.) 
E. Forzsss, A History of British Star-fishes and other animals of the class Echino- 
dermata. Illustrated by woodcuts. London, 1841, 8vo. 
A capital work on the anatomy of this class is : 
F. Trepremann, Anatomie der Réhren-Holothurie, des pomeranz-farbigen Seesterns 
und Stein-Sceigels. Landshut, 1816, folio; a prize Essay crowned by the French 
Institut in 1812. 
W. SHarpry, The article Hchinodermata in Tonn’s Cyclopedia of Anat. and Phy- 
siolog. II. pp. 30—46 (1836). 
J. Mueuter, Ueber den allgemeine Plan der Entwickelung der Echinodermen. Mit 8 
Kupfertaf. Berlin, 1853, 4to, and previous papers in the Abh. d. Akad. der Wissen- 
schaf. zu Berlin 1849, 1850. 
G. L. Duvernoy, Mém. sur VAnalogie de Composition et sur quelques points de 
UV Organisation des Echinoderms. Mém. de V Acad. des Sciences, XX. Paris, 1848. 
