MODERN- SYSTEMS. 287 



The divisions adopted by Leuckart are : Protozoa 

 (though he does not enter upon an elaborate considera- 

 tion of that group), Coelenterata, Echinodermata, Vernies, 

 Arthropoda, Mollusca, and Vertebrata. The classification 

 adopted, many years before, by Siebold, in his text-book 

 of comparative anatomy, is nearly the same, except that 

 the Mollusks follow the Worms, that the Coelenterata and 

 Echinoderms are united into one group, and that the Bry- 

 ozoa are left among the Polyps. 



Here we have a real improvement upon the classifica- 

 tion of Cuvier, inasmuch as the Worms are removed from 

 among the Eadiates, and brought nearer the Arthropods, 

 ah improvement, however, which, so far as it is correct, 

 has already been anticipated by many naturalists, since 

 Blainville and other zoologists long ago felt the impro- 

 priety of allowing them to remain among Eadiates, and 

 have been induced to associate them, more or less closely 

 with Articulates. But I believe the union of the Bryozoa 

 and Kotifera with the Worms, proposed by Leuckart, to be 

 a great mistake ; and as to the separation of the Coelente- 

 rata from the Echinoderms, I consider it as an exaggeration 

 of the difference which exists between the Polyps and Aca- 

 lephs on the one hand, and the Echinoderms on the other. 1 



1 The readiness with which the class, founded upon a special mode 



German naturalists have acquiesced of execution of the plan which distin- 



in the proposition of Leuckart to guishes the Radiata from the other 



unite the Polyps and Acalephs into branches of the animal kingdom, 



one class, seems to be owing to the Their investigations have truly shown, 



circumstance that their opportunities what several French naturalists have 



for studying the Polyps have been long maintained, that many families 



chiefly limited to the Actinias. Had of Radiata, long referred to the class 



they been able to extend their invcs- of Polyps, such as the Hydroids, can- 



tigations to the Astrseans and Madre- not be separated from the Acalephs , 



pores, and to the many types of Haley- but they have been misled, by the 



onoids which characterize the Faunas evidence thus obtained, to an exag- 



of the tropics, they could not have geration of the affinities of the Aca- 



failed to perceive that the Polyps lephs and Polyps. The Polyps, as a 



constitute for themselves a distinct class, differ from the Acalephs in ex- 



