106 Mr. J. D. Dana on Zoophytes. 



the union of the Actinaria and Alcyonaria into a single group, 

 Actinoidea, equivalent in importance to Hydroidea. Blainville 

 was the first author who actually introduced coral zoophytes 

 fairly into the animal kingdom by his mode of describing and 

 arranging them. He did not call the department a branch of 

 zoology, and then describe corals as if they were porous, stelli- 

 gerous stones, which is even now in many instances the case*. 

 Still he speaks of the cells as containing the polyps, which is the 

 reverse of the fact. 



Ehrenberg in 1834f, after a more thorough acquaintance with 

 coral animals obtained by investigations in the Red Sea, made 

 some important improvements in the minor subdivisions ; but his 

 grand divisions were unfortunate. He separated in many cases 

 the attached from the unattached species, and again, the simple 

 from the compound, and thus broke up the natural assemblages 

 which Blainville had made out. Even the natural group Alcy- 

 onaria (Blainville's Zoophytaria) is subdivided by him, and the 

 parts widely separated. His system, notwithstanding some ano- 

 malies, exhibits great reach of mind and searching investigation. 

 He removed correctly the Bryozoa from other Zoophytes, and 

 first suggested the relation of the Millepores and Favosites to 

 the Madreporacea. He pointed out the true nature of coral se- 

 cretions, and described the mode of reproduction by spontaneous 

 subdivision, which had not before been noticed. The modes of 

 growth were also to a considerable extent described by him, and 

 important use made of them, though not always correctly, in the 

 classification of Zoophytes. 



Milne Edwards, whose acquaintance with Zoophytes had been 

 extended by a personal examination of many species, and by a 

 thorough study of the labours of others, besides a comprehensive 

 knowledge of nature, proposed, in 1837, a brief outline of a 

 classification, which, as far as detailed, exceeded those preceding 

 it in philosophical character. The Hydroidea (" Sertulariens"), 

 the Actinaria (" Zoanthaires"), and the Alcyonaria ("Alcyo- 

 niens"), are laid down as the grand divisions, and without the 

 striking violations of affinities which appear in Blainville' s order 

 Polypiaria. We only observe that the Favosites are separated 

 from the Madreporacea, with which group they were placed by 

 Ehrenberg, and where they beyond doubt belong. 



* In descriptions of corals (the internal or basal secretions of Zoophytes), 

 those characters which belong to the Zoophyte ought to be first stated, such 

 as the general form, mode of growth, &c. ; and afterwards, separately, what- 

 ever, not already stated, may require mention with respect to the coral 

 itself. 



f Abhandl. der Kbnigl. Akad. der Wissensch. zu Berlin for 1832, 

 pp. 225-438. 



