CuAP. III. PERIOD OF LINNAEUS. 191 



Insects proper, but also the Mjriapods, the Arachnids, and the Crustacea ; it 

 corresponds more accurately to the division of Arthropoda of modern systematists. 

 The class of Worms, the most heterogeneous of all, includes besides all Kadiata 

 or Zoophytes and the Mollusks of modern writers, also the Worms, intestinal and 

 free, the Cirripeds, and one Fish, (Myxine.) It was left for Cuvier^ to introduce 

 order in this chaos. 



Such is, with its excellences and short-comings, the classification which has given 

 the most unexpected and unprecedented impulse to the study of Zoology. It is 

 useful to remember how lately even so imperfect a perfonnance could have so 

 great an influence upon the progress of science, in order to understand why it is 

 still possible that so much remains to be done in systematic ZoiJlogy. Nothing, 

 indeed, can be more instructive to the student of Natural History, than a careful 

 and minute comparison of the different editions of the " Systema Naturae; " of 

 Linnasus, and of the works of Cuvier and other prominent zoologists, in order to 

 detect the methods by which real progress is made in our science. 



Since the publication of the " Systema Naturas " up to the time when Cuvier 

 jiublished the results of his anatomical investigations, all the attempts at new classi- 

 fications were, after all, only modifications of the principles introduced by Linnteus 

 in the systematic arrangement of animals. Even his opponents labored imder the 

 influence of his master spirit, and a critical comparison of the various systems 

 which were proposed for the arrangement of single classes or of the whole animal 

 kingdom shows that they were framed according to the same principles, namely, 

 under the impression that animals were to be arranged together into classes, orders, 

 genera, and species, according to their more or less close external resemblance. 

 No sooner, however, had Cuvier presented to the scientific world his extensive 

 researches into the internal structure of the whole animal kingdom, than naturalists 

 vied with one another in their attempts to remodel the whole cla.ssification of 

 animals, estaldishing new classes, new orders, new genera, describing new species, 

 and introducino; all manner of intermediate divisions and subdivisions imder the 

 name of families, tribes, sections, etc. Foremost in these attempts was Cuvier 

 himself, and next to him Lamarck. It has, however, often happened that the 

 divisions introduced by the latter under new names, were only translations into 

 a more systematic form of the results Cuvier liad himself obtained from his dis- 

 sections and pointed out in his "Lemons sur ranatomie compar6e," as natural divisions, 

 but without giving thcni distinct names. Cuvier himself beautifully expresses the 



' It would lie injustiop to Aristotle not to nipntinn Speaking, for instance, of the great genera or classes, 



tliat Ik' understood already the relations of the animals he separates eorreetlv the Cei)halopods from the 



united in diii- ila^s liy I>iiui;eus, under the name of other Mollusks, under the name of Malakia. llist. 



AVorms, better than tlie great Swedish naturalist. Anini., Lib. I., Chap. VI. 



