Natural History of British Zoophytes. 2'29 



buminous or calcareous sheath, appropriated solely to support or pro- 

 tection.* 



But although I agree with the advocates of the animality of zoo- 

 phytes in general, I cannot go the length of Ellis in considering it 

 proved that sponges and corallines belong to the same class. Ellis, 

 we have seen, knew that no polypes were to be found in sponge, and 

 their existence in the pores of corallines was inferred merely from the 

 structure of these and their chemical composition. They have been 

 examined by subsequent naturalists fully competent to the task, and 

 under the most favourable circumstances, — in particular by Cavolini 

 and Schweigger, — and the result has been a conviction that these 

 productions are truly apolypdus. Now this fact, in my opinion, 

 determines the point, for if they are not the productions of polypes, 

 the zoologist who retains them in his province must contend that 

 they are individually animals, an opinion to which I cannot as- 

 sent, seeing that they have no animal structure or individual organs, 

 and exhibit no one function usually supposed to be characteristic of 

 that kingdom. Like vegetables they are permanently fixed, — like 

 vegetables they are non-irritable, — their movements, like those of 

 vegetables, are extrinsical and involuntary, — like cryptogamous vege- 

 tables or algse they usually grow and ramify in forms determined by 

 local circumstances, and if they present some peculiarities in the 

 mode of the imbibition of their food and in their secretions, yet even 

 in these they evince a nearer affinity to plants than to any animal 

 whatever. 



II. — On the Structure and Functions op the Polypes 



ABSTRACTEDLY CONSIDERED. 



On the continent the term Zoophyte has of late been used in a 

 very extensive sense, so as to include every animal which exhibits 

 a circular disposition of parts radiating from a common centre, and 

 many also in which this character is little or not at all obvious. In 

 this country the word has never been so employed excepting in trans- 

 lations from a foreign language : no English writer ever thinks of 

 calling an intestinal worm, or a sea-jelly, or a star-fish, or even the 



* I do not enter into the question whether the Confervae are real animals or 

 not, because,- whatever conclusion we might adopt, they would not come within 

 our definition of a zoophyte or polype^ since they assuredly have neither mouth, 

 tentacula, nor stomach. Nor need I discuss the propriety of instituting, with 

 Treviranus, a fourth kingdom of animated nature, composed of the zoophytes 

 and aquatic cryptogamia, as my object and plan is only to describe what have 

 been almost universally considered zoophytes. 



NO. III. Q 



