A LIST OF THE GENERA AND FAMILIES OF MAMMALS. b? 
Systematic zodlogy, or the practice of classification, has failed to keep pace with 
the principles of the science; we are greatly in need of some new and sharper ‘ tools 
of thought,’ which shall do for zoólogy what the system of symbols and. formulze 
have done for chemistry. We want some symbolic formulation of our knowledge. The 
invention of a practical scheme of classification and nomenclature, which should 
enable us to formulate what we mean by Turdus migratorius as a chemist symbolizes 
by SO,H, what he understands hydrated sulphuric acid to be, would be an inesti- 
mable boon to working naturalists. (Key N. Am. Birds, 2d ed., 78, 1884.) 
To a certain extent this is done in some paleontological names. 
Thus words compounded with -therdwm, or with the prefixes amphi-, 
€0-, epi-, Limno-, meso-, meta-, mto-, plesio-, plio-, and proto-, are almost 
always used for extinct genera” and should be reserved exclusively 
for them. Prefixes may be briefly and conveniently used to express 
relationship. Amphicyon, Epicyon, and Pseudocyon, all indicate groups 
more or less closely related to the dogs; Cimolestes, a marsupial from 
the Cretaceous; Lohippus, Miohippus, and Pliohippus were proposed 
for horses which existed in the Eocene, Miocene, or Pliocene; /"oto- 
dichobune for a type of artiodactyl which preceded, and MWetadichobune 
for one which followed, DeAobune. 
Pliohippus means an animal from the Pliocene related to the modern 
horse; JMioszren, an animal from the Miocene related to modern sire- 
nians; and Zmnof^lis, an animal found in an old morass and related 
to living cats, etc. Here the names give (a) the designation of the 
genus, (b) its geological position, and (c) its relationship; while their 
form indicates (d) that the genera are extinct. 
In order to illustrate the great variety of compounds which can be 
made from one word, and at the same time to furnish a ready refer- 
ence list which may be useful in coining new names, it has been deemed 
desirable to give the compounds of six of the words most frequently 
used in making generic names of mammals. These words are: yay, 
weasel; Z«r:c, weasel; upvé, ruminant; ps, mouse; vUKTEpis, bat; 
od0vs, tooth. As will be seen by reference to the lists, the com- 
pounds of these words vary from 39 in the case of pn pvé, to 350 in the 
case of 0s, and to more than 450 in that of 0900s. In other words, 
about 8 percent of all the generic names of mammals are compounds 
of 4s and more than 10 percent of the entire number are compounds 
of odovs, 


“There are a few exceptions, such as Amphiaulacomys, Amphisorex, Ceratotherium, 
Dorcatherium (originally applied to an extinct group since found to have living 
representatives), Konycteris, Eosciurus, Eothenomys, Eoxerus, Eozapus, Epünys, Epio- 
don, Limnogale, Limnolagus, Mesobema, Mesocricetus, Mesomys, Mesoplodon, Metachirus, 
Miopithecus, Protoxerus, but the rule holds good in nine cases out of ten. The dis- 
crepancy in the case of eo is due to its double signification of ‘eastern’ when used 
for recent genera, and ‘dawn’ for extinct groups. Full lists of the genera with 
these 10 prefixes, aggregating about 180 names, will be found in the body of the 
‘Index.’ . 
