INTRODUCTION. ix 
Sus-cuass l. 
CORALLARIA. 
Actinoidea, Dana. Op. cit., p. 16, 1846. 
Polypi possessing distinct internal reproductive organs, and having the gastric or 
visceral cavity surrounded by vertical, radiating, membranaceous lamelle. 
In this division of the class of Polypi, the Corallum is in general calcareous, and may be 
either tubular, cyathoid, discoidal, or basal; but never assumes the form of cylindrical, 
tubular, horny sprigs, bearing simple bell-shaped cells, for the reception of the contracted 
tentacula, as we usually find in the sub-class of Hydraria. 
Corallaria present three principal structural modifications, and must therefore be 
subdivided into three corresponding groups or orders: Zoantharia, Alcyonaria, and 
Podactinaria. 
Orper |. 
ZOANTHARIA. 
Zoanthaires (Zoantha), Blainville. Manuel d’Actinologie, p. 308, 1834. 
Zoanthaires (Zoantharia), Milne Edwards. Elém. de Zoologie, p. 1045, 1835; Annot. de Lamarck, 
Anim. sans Vertéb., tom. ii, p. 106, 1836. 
Zoophyta helianthoidea, Johnston ; in Mag. of Zool. and Bot., vol. i, p. 448, 1837; Hist. of British 
Zoophytes, p. 207, 1838. 
Zoantharia, J. E. Gray. Synop. Brit. Mus., 1842. 
Actinaria, Dana. United States Exploring Expedition, Zoophytes, p. 112, 1846. 
Anthozoa helianthoidea, Johnston. Hist. of Brit. Zooph., 2d ed., vol. i, p. 181, 1847. 
Polypi with conical, tubular, simple or arborescent, but not bipinnate, tentacula, and 
with numerous perigastric membranaceous lamine, containing the reproductive organs. 
Zoantharia are in general coralligenous, and almost all the known fossil Polypidoms 
belong to this natural group of Zoophytes. 
These Corals are very seldom essentially composed of epidermic tissues, nor do they 
scarcely ever constitute basal stems, as is usually the case in Alcyonaria. They are almost 
always formed of calcified dermic sclerenchyma, and inclose, more or less completely, the 
inferior portion of the great visceral or gastric cavity of the Polyp. Each individual has in 
general the form of a deep cup or a tubular sheath, the cavity of which is subdivided into a 
circle of loculi, by vertical septa affecting a radiate disposition. No trace of any such septa 
is ever met within Corals belonging to other animals of the same class, and although these 
parts are sometimes rudimentary in Zoantharia, the starlike appearance of the calice pro- 
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