Vill BRITISH FOSSIL CORALS. 
CLASSIFICATION OF POLYPI. 
Sus-kinapom ZOOPHYTA; Srcrion RADIATA. 
Cass 
POLYPI. 
Animals of the sub-kingdom of Zoopnyta, and of the section of Raptrara,’ organized 
for a sedentary mode of life, having no locomotive organs, and being provided with a circle of 
retractile tentaculz around the mouth, anda central gastric cavity, not communicating with 
an anus, and containing the reproductive organs when these exist ; in general fissiparous, 
or multiplying by buds as well as by ovules. 
The systems adopted by Cuvier, Lamarck, Lamouroux, and their contemporaries, for the 
subdivision of the class of Polypi, were founded on external characters of very little value, 
and were quite artificial. In a Memoir, published about twenty years ago,” a first attempt 
was made to establish this classification on anatomical facts, and the Zoophytes presenting 
the above-mentioned structure were distributed in two groups, characterised by the pre- 
sence or the absence of internal ovaria, and a membranaceous tube leading from the mouth 
to the great gastric cavity. Subsequent observations have confirmed these views, and 
Mr. Dana, whose recent work® is one of the most valuable contributions which America has 
yet made to Natural History, divides in a similar manner the class of Polypi into two 
secondary groups. We shall continue adopting this classification here; but the name of 
Actinoidea, which Mr. Dana applies to the first of the two sub-classes thus established, 
having been previously employed by other zoologists in a much narrower acceptation, we 
have thought it advisable not to make use of it here, and we propose substituting for it that 
of Corallaria. The second group comprises the Sertularian Polypi (Milne Edw.), and may 
be designated by the name of Hydraria. 
1 The sub-kingdom of Zoophytes may be divided into two natural groups: the one comprising all the 
true Radiate animals (Echinoderma, Acalephze, and Polypi); the other containing the spheroidal or amor- 
phous Zoophytes (such as Spongidee and certain Infusoria). The first ‘may retain the name of Radiata ; 
the second has been designated by that of Sareodaria (Milne Edwards, Cours élémentaire de Zoologie). 
2 Recherches sur les Animaux sans Vertébres, faites aux iles Chausay, par MM. Audouin et Milne 
Edwards (Annales des Sciences Naturelles, premiére série, t. xv, p. 18, Septembre, 1828). 
> United States Exploring Expedition; Zoophytes. Philadelphia, 1846. 
