230 Natural History of British Zoophytes. 



infusory animalcules, a zoophyte ; but he applies the name to no 

 other creatures than those which in their form, or most remarkable 

 characters, recall the appearance of a vegetable or its leading pro- 

 perties. In this restricted sense I also use it in these essays, or ra- 

 ther with a still narrower circumscription, having assigned what ap- 

 pear to be sufficient reasons for removing the corallines and sponges 

 from the category, and restoring them to the vegetable kingdom, to 

 which the earlier naturalists believed they had a rightful claim. The 

 definition of a zoophyte is thus considerably simplified, but there 

 remains sufficient variety and discrepancy in the constituents of the 

 order to render that definition in some degree vague and incongruous. 

 The fact is — the classification of molluscous, and radiated, and acri- 

 tous animals requires to be recast : the limits between them have not 

 been determined with undisputed precision, and it seems probable 

 that there are in each class some tribes which will pass from one to 

 the other as discovery proceeds. It has been recently proposed* to 

 remove a large proportion of zoophytes hitherto considered legiti- 

 mate subjects of their order to the mollusca, which, about the year 

 1815,t had received a considerable accession to its numbers from 

 the same source; but so far from acknowledging the propriety of the 

 proposed translation, I incline to agree with Lamarck;}; that it would 

 be better to separate again the colonized zoophytes from the mollusca, 

 and form with them, and with such zoophytes as have an analogous 

 organization, a distinct class, to occupy the wide interval between 

 the molluscan and radiated types, allied to the former by the non- 

 symmetrical figure of the body, and to the latter by the circularity 

 of the oral members. It is, however, unnecessary to enter here upon 

 this discussion, for my intention is to describe what are usually 

 reckoned zoophytes, without having regard to the naturalness of the 

 group considered as a whole, and with this view I adopt the class as 

 it was long ago established by Solander and Ellis, excepting only 

 the corallines and sponges, which will form the subject of separate 

 monographs. The following definition may serve to characterize the 

 class : 



Animals avertebrate, inarticulate, soft, irritable and contractile, 

 without a vascular or separate respiratory or nervous system : mouth 

 superior, central, circular, edentulous, surrounded by tubular or more 



* Thompson's Zoological Researches and Illustrations, p. 92. 

 f Savigny's Memoires sur les Animaux sans Vertebres. Seconde Partie. Pa- 

 ris, 1816, 8vo. 



\ Hist. Nat. des Anim. s. Vert. iii. 82 — 87. 



