212 ESSAY ON CLASSIFICATION 



nous Fishes, a retrogTade movement suggested by some inaccurate 

 observations of Dr. Garden. ^^ Tlie class of Fishes is very well limited 

 in the early editions of the Systema, with the exception of the ad- 

 mission of the Cetaceans (Plagiuri) which were correctly referred 

 to the class of Mammalia in the tenth edition. In the later editions, 

 however, the Cyclostoms, Plagiostoms, Chimaeras, Sturgeons, Lophi- 

 oids. Discoboli, Gymnodonts, Scleroderms, and Lophobranches are 

 excluded from it and referred to the class of Reptiles. The class of 

 Insects,^^ as limited by Linneeus, embraces not only what are now 

 considered as Insects proper, but also the Myriapods, 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 Radiata 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 shortcomings, 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 performance 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 Zoology. Nothing indeed 

 can be more instructive to the student of Natural History than a care- 

 ful and minute comparison of the different editions of the Systema 

 Natiira of Linnaeus, 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 Natures up to the time when 

 Cuvier published the results of his anatomical investigations, all the 

 attempts at new classifications were, after all, only modifications of 



^ [Alexander Garden, 1730?- 1791.] 



^ Aristotle divides this group more correctly than Linnaeus, as he admits already 

 two classes among them, the Malacostraca (Crustacea) and the Entoma (Insects). Hist. 

 Anim., Lib. I, Chap. 6. VL He seems also to have understood correctly the natural 

 limits of the classes of Mammalia and Reptiles, for he distinguishes the Viviparous 

 and Oviparous Quadrupeds and nowhere confounds Fishes with Reptiles. Ibid. 



^It would be injustice to Aristotle not to mention that he understood already the 

 relations of the animals united in one class by Linnaeus, under the name of Worms, 

 better than the great Swedish naturalist. Speaking, for instance, of the great genera 

 or classes, he separates correctly the Cephalopods from the other Mollusks, under the 

 name of Malakia. Hist. Anim., Lib. I., Chap. 6. 



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