318

ESSAY ON CLASSIFICATION.

instead of recognizing at the outset these great plans, heallows the external form to be the leading idea uponwhich his primary divisions are founded, and thus hedivides the animal kingdom into three sub-kingdoms: thefirst including his Artiozoaria, with a bilateral form ;the second his Actinozoaria, with a radiated form; andthe third his Heterozoaria, with an irregular form (theSponges, Infusoria, and Corallines). The plan of struc-ture is only introduced as a secondary consideration, uponwhich he establishes four types among the Artiozoaria:1st. The Osteozoaria, corresponding to Cuvier ’s Verte-brata; 2nd. The Entomozoaria, corresponding to Cuvier ’sArticulata ; 3rd. The Malentozoaria, which are a veryartificial group, suggested only by the necessity of esta-blishing a transition between the Articulata and Mol-lusca; 4th. The Malacozoaria, corresponding to Cuvier ’sMollusca . The second sub-kingdom, Actinozoaria, cor-responds to Cuvier ’s Eadiata, while the third sub-king-dom, Heterozoaria, contains organized beings which forthe most part do not belong to the animal kingdom.Such at least are his Spongiaria and Dendrolitharia, whilsthis Monadaria answer to the old class of Infusoria, aboutwhich enough has already been said above. It is evident,that what is correct in this general arrangement is bor-rowed from Cuvier ; but it is only justice to De Blainville to say, that, in the limitation and arrangement of theclasses, he has introduced some valuable improvements.Among Yertebrata, for instance, he has distinguished, forthe first time, the class of Amphibia from the true Rep­ tiles . He was also the first to remove the IntestinalWorms from among the Eadiata to the Articulata; butthe establishment of a distinct type for the Cirripedia andChitons was a very mistaken conception. Notwithstand-