HYDEOID ZOOPHYTES. 33 



a resemblance to shrubs^ mosses, and seaweeds, while show- 

 ing some signs of animal life, that it is not surprising that 

 a name should be used significant of both ideas ; but at pre- 

 sent, those only are retained in the assemblage whose na- 

 tures have been ascertained to be strictly animal, and not 

 to partake in any degree of a vegetable character. All the 

 true Zoophytes are polypiferous in their structure, and are 

 thus defined by Johnston, who is the great authority on 

 the subject. 



" Zoophytes are all aquatic, avertebrate, inarticulate, soft, 

 irritable, and contractile, without a vascular or separate 

 respiratory or nervous system. The alimentary canal is 

 very variable, but the aperture to it is always superior, cir- 

 cular, edentulous, and surrounded by tubular, or more com- 

 monly by filiform tentacula. Many are asexual, and it is 

 doubtful whether any species has distinct sexes. The indi- 

 viduals, polypes, of a few families are separate and perfect 

 in themselves; but the great majority of Zoophytes are com- 

 pound animals, viz. each Zoophyte consists of an indefinite 

 number of individuals, or polypes, organically connected, and 

 placed in calcareous, horny, or membranous cases or cells, 

 forming, by their aggregation, corals, or plant-like poly- 

 pidoms/^ 



1) 



