OCTOBEB 18, 1907] 



SCIENCE 



491 



it. Although Ray had already recognized 

 four of the great groups or classes of verte- 

 brates, he had not named them and there 

 were vernacular terms only for the birds 

 and fishes. Linne, for the first time, ap- 

 plied names to the other groups, and ad- 

 mirable ones they were. Mammalia and 

 Amphibia were the coinage of Linne and 

 are still retained; Mammalia or mammals 

 by all; Amphibia or amphibians by the 

 majority for one of the classes now 

 adopted. 



A great advance, too — an inspiration of 

 genius, indeed— was the segregation of the 

 animals combined under the class of mam- 

 mals. Popular prejudice was long uni- 

 versal and is still largely against the 

 idea involved. Sacred writ and classical 

 poetry were against it. It seemed quite 

 unnatural to separate aquatic whales from 

 the fishes which they resembled so much in 

 form and associate them with terrestrial 

 hairy quadrupeds. How difficult it was to 

 accustom one's self to the idea is hard for 

 naturalists of the present day to appre- 

 ciate. Linne liimself was not reconciled 

 to the idea till 1758, although Ray had 

 more than hinted at it more than three- 

 score years before. At last, however, in 

 no uncertain terms, he promulgated it. It 

 was a triumph of science over popular im- 

 pressions ; of anatomical consideration over 

 superficial views. 



But mingled with the great benefactions 

 were many views which long influenced 

 naturalists, but which modern zoology has 

 overthrown. 



lilNN^EAN CLASSES 



After the tentative arrangements pub- 

 lished in the original first, second and sixth 

 editions of the "Systema," Linne thor- 

 oughly revised his work, and fii-st consist- 

 ently applied the binomial method of nom- 

 enclature to all species in the tenth edition, 

 published in 1758. Six classes were ad- 



mitted with equal rank, no category being 

 recognized between the class and kingdom. 

 The classes were the Mammalia or Mam- 

 mals, Aves or Birds, Amphibia, Pisces, 

 Insecta and Vermes. The first four of 

 these classes mainly correspond with the 

 Aves and nameless groups of Ray. 



During the Linncean period of activity 

 the invertebrates were little understood, 

 and his treatment of that enormous host, 

 referred to his two classes Insecta and 

 Vermes, contrasts rather than compares 

 with that at the present time. Naturally, 

 the vertebrates were much better compre- 

 hended, and all such then known, with a 

 single exception, were distributed among 

 four classes just named, the Mammalia, 

 Aves, Amphibia and Pisces. The solitary 

 exception of exclusion of a true vertebrate 

 from its fellows was the reference of the 

 genus Myxine to the Vermes, next to Te- 

 redo, the ship-worm. The first two classes 

 were adopted with the same limits they 

 now have, but the Amphibia and Pisces 

 were constituted in a truly remarkable 

 manner. The class of Amphibia was a 

 creation of Linne, and was simply con- 

 trasted with his Pisces by having a lung 

 of some kind {"piilmone arhitrario"), 

 while the Pisces have exposed branchiae 

 {"branchiis externis"). The Amphibia, 

 thus defined, were made to include as 

 orders: (1) Reptiles or Reptilia, having 

 feet; (2) Serpentes, footless, and (3) 

 Nantes, having fins. 



Under the Nantes were first grouped 

 the lampreys, the selachians, the anglers 

 (Lophiv^), and the sturgeons (Acipenser). 

 In the twelfth edition were added Cyclop- 

 terus, Balistes, Ostracion, Tetraodon, Bio- 

 don, Gentriscus, Syngnathus and Pegasus. 

 The Nantes were added to the Amphibia 

 partly because of the assumption that the 

 branchial pouches of the lampreys and 

 the selachians were lungs and partly on 

 the authority of Dr. Alexander Garden, 



