Natural History of British Zoophytes. 447 



mouroux and Lamarck entertained a very different opinion. The 

 former, with feigned regret of the hopelessness of an anatomical 

 method, and with a conviction of its inapplicability if attained, pro- 

 ceeded to arrange and subdivide the class on the ground of differ- 

 ences in the chemical composition of the polypidoms ; and the latter, 

 assuming that their cells and corals were an exact cast or mould of 

 the features of the polypes, and hence that a sameness in the struc- 

 ture and form of the one necessarily implied a correspondency in the 

 structure of the other, invented a system which he has, with a com- 

 placency that is almost ludicrous, pronounced to be in exact harmony 

 with the march of nature in her creations, or, to use a language more 

 becoming us, with that plan upon which the Author of Nature has 

 apparently proceeded in calling his creatures into existence. We 

 shall analyze these systems hereafter : it is at present sufficient to 

 say, that the result of their labours has been a very preposterous 

 combination of species and genera, — separating, in many cases, what 

 is nearly affined, and, in other instances, assorting together what are 

 most alien. There is indeed no safer course for the systematist than 

 that pointed out more especially by Blainville : the anatomy of the 

 polypes must be the basis of his primary divisions, while in the com- 

 position of the polypidoms he may possibly find characters to discri- 

 minate and circumscribe the secondary groups in the absence of that 

 more certain knowledge which the comparative anatomist has yet 

 failed to give him. On this principle we now attempt to classify 

 the British Zoophytes, which it is proposed to divide, in the first 

 place, into the following sub-classes and orders. * 



Sub-class I. Radiated Zoophytes. 



Body contractile in every part, symmetrical j mouth and anus one ; 



always gemmiparous ? 



Order [. Hydroida. Polypes compound, rarely single and naked, 

 the mouth encircled withroughish filiform tentacula; stomach with- 

 out proper parietes ; intestine ; anus ; reproductive gem mules 

 pullulating from the body and naked, or contained in externa] ve- 

 sicles. Polypidoms horny, fistular, more or less phytoidal, fixed, 

 external. Marine, excepting Hydra, which is lacustrine. 



Order II. Asteroida. Polypes compound, the mouth encircled 

 with 8 fri?iged tentacula ; stomach membranous, with dependant 

 vasculiform appendages ; intestine ; anus ; reproductive gem- 

 mules produced interiorly. Polype-mass variable in form, free or 



* The classification indicated by Audouin and Milne- Edwards seems in exact 

 harmony with the one here adopted. Recherches pour servir a l'Histoire Nat. 

 du Littoral de la France, Vol. i. p. 73 — 6- 



