VOL. 1. ] Colors of West Coast Mammals. 209 
this case, also, natural selection would be the secondary cause, the 
variations being directed in a certain channel by the immediate 
action of environment. 
Dr. Harrison Allen has published a paper on the “ Distribution 
of Color Marks of the Mammalia,”* in which he attributes many of 
the markings of mammals to excess of nourishment near the surface 
in particular areas, and attempts to correlate them with the presence 
of nerve terminals, masses of muscle, etc. This is an interesting and 
important line of investigation, and his theory appears to have much 
plausibility in it, but lam unable to find a single fact in regard to 
the markings of west coast mammals which lends any particular 
support to the theory, and it would seem that its applicability should 
be a very general one if it had any force whatever. That there are 
some deep-seated mechanical causes at work, however, in the pro- 
. duction of many of the characteristic patterns or regions of color 
_ marks seems highly probable, to say the least. 
There are few groups in the animal kingdom in which brilliant 
color is so conspicuously absent as among mammals. This fact 
can be accounted for in two ways: by the greater need for protec- 
tion incident to a terrestrial life, and by the fact that the majority of 
mammals are more or less nocturnal in their habits. Brilliant colors 
would therefore be of no use, but on the contrary would be posi- 
tively harmful. There is another class of colors to which Wallace 
has called particular attention, and which are very frequently present 
among mammals, viz: recognition markings. Mr. J. E. Todd, ap- 
parently without having consulted Wallace on the subject, arrived 
at about the same theory in regard to this class of colors. He calls 
- them directive colors, and by their aid attempts to account for nearly 
all the special markings of mammals and birds. It appears to 
me that both he and Wallace attribute too much to this factor, 
* although it is doubtless of great importance and of wide application. 
‘3 Supposing that natural selection has been the means of producing 
_ these recognition marks, it must not be forgotten that here, as in the 
example first considered, there must be some creative and directive 
force behind it. But could natural selection have had a hand in bring- 
ing about these recognition markings? Wallace,t in discussing the 
~ *Proc. Acad. Nat. Sci. Phil., 1888. 
_ tAmerican Naturalist, xxii, 1888, pp. 201-207.. 
_ -{Darwinism, p. 218. 
