OF POLYPES. 31 



portion of zoophytes hitherto considered legitimate subjects of 

 their order to the molhisca, which, about the year 1815,* had 

 received a considerable accession to its numbers from the same 

 source; but so far from acknowledging the propriety of the pro- 

 posed translation, I incline to agree with Lamarckf, 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 contrac- 

 tile, loithout a vascular or separate respiratory or nervous sys- 

 tem : mouth superior, central, circular, edentulous, surrounded by 

 tubular or more commonly by Jilifurm tentacula ; alimentary ca- 

 nal variable, — where there is an intestine the anus opens near 

 the mouth: asexual; gemmiparous : aquatic. — The individuals 

 (Polypes) of a few families are separate andperfect in themselves, 

 hut the greater number of zoophijtes are compound beings, viz. 

 each zoophyte consists of an indefinite number of individuals or 

 polypes organically connected and placed iv a calcareous, horny 

 or membranous case or cells, forming, by their aggregation, 

 corals or plant-like Polvpidoms. 



In this definition there are two parts which require our par- 

 ticular attention — the Polype whose presence is essential, and 

 the Polypidom,X which is the house or support of the polype, 



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

 ris, 1816, 8vo. 



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



\ I borrow this term from the translator of Lamouroux's work on Corallines. 

 The Rev. Mr Kirby, in his Bridgewater Treatise, uses the word Pohjpary to ex- 

 press the same thing. Both of them are translations of Puhjpier, a word in- 

 vented by Reaumur, and now in general use among the French naturalists. 



