42 INDEX GENERUM MAMMALIUM. 
until invested with one by being used as a handle of a fact; and the 
meaning of a name so used, in zoological nomenclature, does not 
depend on its signification in any other connection” (Principle V). In 
spite of this declaration, it will be found that most generic names have 
been bestowed for the sake of drawing attention to some characteristic 
or resemblance of the animal, fancied or real. They may contain many 
facts of interest, descriptive, geographical, or historical, and the 
knowledge of such derivation may be, and often is, an aid in keep- 
ing in mind the relationship of the group. Unfortunately, very few 
authors have taken the trouble to give etymologies or explain the 
application of their generic names.“ Agassiz gave derivations in his 
* Nomenclator Zoologicus’ and his example has been followed in this 
list, but the result is often unsatisfactory. In some cases it is almost 
impossible to tell what the derivation is, and in others the derivation 
may be clear, but the application very obscure. Some of the explana- 
tions are probably erroneous, but with no guide or hint from the 
author the determination of etymology is oftentimes little better than 
guesswork. Liddell & Scott's Greek-English Lexicon and Harper's 
Latin Dictionary have been followed for classical words, and liberal 
use has been made of the Century Dictionary. In a few cases the 
authorities have been given for explanations of barbarous names or 
those of unusual meaning. 
ETYMOLOGY OF THE WORD 'MAMMAL.' 
Before discussing the derivation of generic names it may not be out 
of place to refer briefly to the etymology of the word ‘mammal,’ which 
Dr. Theo. Gill’ has recently elaborated. One of the best authori- 
ties, the Century Dictionary, gives the following explanation of 
the word: 
Mamma, a. and n. [— OF. mammal =Sp. mamal= Pg. mamal, mammal — It. 
mammale, n.; « NL. mammale, a mammal, neut. of LL. mammalis, of the breast, 
« L. mamma, the breast]. 
This derivation, as shown by Dr. Gill, is misleading: 
The name mammalia was first coined and used by Linnzeus in 1758, and was 
formed directly from the Latin; it had nothing to do with French, Spanish, Portu- 
guese or Italian words. . . . 
It was one of tbe happiest inspirations of Linnzeus to segregate all the mammiferous 
animals—the hairy quadrupeds, the sirenians, and the cetaceans—in a single class. 
No one before had appreciated the closeness of the relations of the several types, 

«Exceptions to the rule are Illiger, Owen, and Waterhouse, who explained the 
etymology of their names. Gaudry gives many derivations in his * Enchainements 
du Monde Animal’. Dr. D. 8. Jordan explains the etymology of all the mammal 
names which occur in his ‘Manual of Vertebrates’, and the late Prof. O. C. Marsh 
gave derivations in the lists of his new genera, published for private circulation, and 
also in Scudder’s *Nomenclator Zoologicus'. The application of many names will 
also be found in Beddard’s ‘Mammalia’, 1902. 
b‘The Story of a Word—Mammal,’ Pop. Sci. Monthly, LXI, pp. 484-438, Sept., 
1902. 
