224 ON THE CLASSES OF THE 



logy as deserving a severer epithet than vague, Avhich has 

 been used in order to unite the Entozoa with the Echino- 

 derma. Because some of the Intestiriaux of Cuvier have 

 two fibrous hnes, or muscular threads, shooting out from 

 a circle round their mouths, it has been asserted that 

 these animals afford traces of a radiated structure; but 

 other naturalists appear to have drawn from the same 

 observation a much more correct conclusion, in con- 

 ceiving that these two fibres, where they exist, are but 

 modifications of the ordinary nervous system of the An- 

 nulosa, allowance being made for their being animals far 

 more im]oerfect than the usual t}pes of this system of 

 construction. It seems indeed impossible in an arrange- 

 ment wliich has any pretensions to being natural, to sepa- 

 rate some of tlie Entozoa, such as the Nematoidea of 

 Rudolfi, far from Lumbricus and Gordius. 



With respect to this new division of animals, which I have 

 called Acrita, the following definition, which is nearly that of 

 Lamarck, will serve to exclude such of the Intestbiaux of 

 Cuvier as deserve a higher place in the scale of nature. 



Aubnalia gelatbwsa polymorpha, intcruneis nullis me- 

 duUaque indistbictu. 



Os interdum indistinctum, sed nutritio ahsorptione ex- 

 terna vel interna semper sistit. Anus uullus. 



Reprodnctio Jissipara vel gemmipara, gemmis modo ex- 

 ternis modo iniernis, interdum acervatis. 



Pleraqne ex iiidividuis pluribus semper coharentihus ani- 

 malia composita sisiunt. 



The distinctive character of these animals is therefore 

 principally negative as referred to animals, and positive 

 as referred to plants. The simple texture of their cellular 

 tissue is common to them with the Algae ; their geramipa- 



