22 
for the principle is the same, the differences being merely relative, 
not absolute. 
We have already assumed that certain relationships do exist among 
organic beings, that certain species are more nearly united by blood 
than others, and that therefore groupings of these naturally allied 
individuals are possible. By collecting all the most nearly allied 
species together we obtain various genera; by collecting the most 
nearly allied genera we get tribes, and so on. 
The closely allied individuals which form a genus will, as it were, 
congregate around a certain individual, which will possess more 
features in common with the others than any other one of them will, 
and could we detect this individual, we should have the natural type 
of the genus; but we know that various physical phenomena—floods, 
rising and sinking of the land, volcanic action, &c.—have, in the 
course of ages, rendered many species extinct, and we are also aware 
that our own knowledge, even of existing species, is so fragmentary, 
that the search for the typical individual of each natural group, 2. e. 
the centre from which the group has sprung, is a difficult one, and, in 
many cases, practically hopeless at the present time. Such a type 
would be, as it were, placed in the centre of a sphere; whilst the 
species included in the same genus with it would represent complete, 
incomplete, aborted, or branched radii, striking out in all or any direc- 
tion towards the surface of the sphere. 
It will be seen, then, that the “genus” and the ‘‘species” differ in 
significance. ‘The genus is indicative of the relationships held by a 
group of various closely allied individuals to other similar groups in 
the organic world, and depends upon the various structural pecu- 
liarities which the individuals comprising it possess in common, 
whilst the ‘‘species” indicates the actual creature itself; in other 
words, the one applies to several individuals or races with distinct 
peculiarities, though bound together by broad structural charac- 
teristics, the other applies to a single individual race alone. 
One may be met by the query—already in reality answered in the 
earlier part of the paper—why, if the specific name indicates the 
species, do we want a generic name at all, for the former indicates 
the animal itself? and this was the position of those who, more than 
half a century ago, brought forward the ‘*‘ Mononomique Méthode” of 
nomenclature. Such reasoning may be at once met by pointing out 
that not only do we want a name (specific) to designate the 
individual itself, but also another name (generic) to show its 
relationship to the creatures immediately allied to it, and yet 
others (tribal, sub-family, and family) to indicate its relationship 
to those more distantly allied. 
The misconceptions of the generic theory which end in the 
belief that genera are either (1) purely imaginary, or (2) have a 
definite and isolated existence, are undoubtedly responsible for the 
assumption that a mononomic system is possible, and the latter idea 
applied to species has also led to gross error, although, because 
