12 LIVERPOOL BIOLOGICAL SOCIETY. 
characters by which the species differ from one another 
and the observed mode of life. 
This as you can see will be a very large piece of work, 
as it involves a re-examination of all accessible species 
in a state of nature, but it is an investigation well worth 
making. It will give a new and very real importance to 
faunistic and speciographic work, and it will be greatly 
aided by the numerous biological stations which are being 
established on the coasts of Hurope and America, as by 
means of these institutions it has now become possible 
for the first time to work satisfactorily at marine animals 
in a living state. Moreover this work if properly carried 
out will lead to a careful revision of the specific characters 
of allied forms in many groups of animals, in itself a very 
desirable object, for all systematists know how much the 
specific characters of some groups are in need of revision. 
The definitions of most genera and species are pre- 
Darwinian, if not in date at. least in conception. Genera: 
and species have been regarded by most systematists 
as sacred and immutable things, and moreover as being 
totally different from one another, but we now know 
as evolutionists that a genus is only a greater or more 
emphasized species—that is to say, it is only an assemblage 
of individuals which have become more widely separated 
morphologically from their fellows (see the accompanying 
diagram). Consequently, there can be no important 
difference in kind between specific and generic characters. 
It has sometimes been said that specific characters may 
be useful to their possessors, but that generic characters 
need not be so; that I cannot allow. Generic characters 
being as it were emphasized specific characters, if the 
latter are useful the former must be still more so, and the 
same argument applies to the characters of families, and 
other larger groups. | 
ee a A, ea a ee 
ee 
eee ee oe Ee ee a 
