34 INDEX GENERUM MAMMALIUM. 
or presence or absence of aspirates. Some eminent zoologists maintain 
that a difference of a single letter in two names is sufficient to pre- 
vent the later one from being preoccupied, and cite such cases as 
Picus and Pica, Galeus and Gale, in support of their position. It is 
generally admitted that these names should all stand, since they are 
taken from classical words which were originally applied to very dis- 
tinct organisms; and the validity of this argument is generally recog- 
nized in spite of Principle V of the A. O. U. Code, which declares 
that **a name is only a name, having no meaning until invested with 
one by being used as the handle of a fact, and the meaning of a name 
so used in zoological nomenclature does not depend upon its signifi- 
‘vation in any other connection.” While the question of derivation 
does not necessarily enter into the availability of a name, it may serve 
a useful purpose as a guide in deciding whether names are preoccupied 
or not, as will be seen by some of the examples cited later. A large 
number of names comprise derivatives and compounds of the same 
Greek or Latin words. These names may have different forms: 
(a) According to gender, as Otostomus, Otostoma, Otostomum. 
Otostomis Menke, 1830, a mollusk; Ofostomus Beck, 1837, a mollusk; 
Otostoma Carter, 1856, a protozoan; Otostomum Ehrenberg, 1872, a 
. : » 
protozoan, all evidently derived from the same Greek words, ovs, ear, 
and erój«, mouth. 
(b) According to the particular Greek dialect from which the words 
have been selected, as Lampronessa and Lampronetta. Both these 
names are compounds of Lapzpos, splendid, and vgrr«, duck; but in 
the former the Epic or Ionic form, v766«, is used and in the latter its 
Attic equivalent, vzrre«. 
(c) According to whether the original Greek form has been pre- 
served or whether it has been transliterated into Latin form, as /Z/p- 
posideros and [ipposiderus. 
(d) According to whether the Greek aspirate has been preserved 
or not, as Abrothrix and Habrothrir; Reithrodon and Rhithrodon. 
(e) According to whether the connecting vowel 1 or o has been used 
in compounding two classical roots, as Callorhinus and Callirhinus. 
It is therefore possible to make a number of compounds from the 
same words, all meaning the same thing, and differing from one another 
simply by a letter or two. This may be illustrated by compounds of 
Kados,” beautiful, and 42s, mouse. The following list contains no less 
than 16 variations compounded from these words in accordance with 
classical rules, two of which, Calomys and Callomys, have actually been 
proposed for different genera of mice. 

Calimys. Calimus. Kalimys. Kalimus. 
Calomys. Calomus. Kalomys. Kalomus. 
Callimys. Callimus. Kallimys. Kallimus. 
Callom ys. Callomus. Kallomys. Kallomus. 

“See also footnote under Callidon, p. 151. 
