160 The American Naturalist. [Febrnary, 
-of the breeding season shows, however, that this is not the true explana- 
tion. Among the hundreds of redfish that we examined as they came 
up into Alturas Inlet from the lake not one possessed any sores, or had 
the fins frayed out in the least; every one was perfect in every way, 80 
far as mutilations were concerned. Not only were all of those caught 
on the gill nets as they came up from the lake free from sores, but no 
sores were seen on any of the fish in the creek until some time after the 
spawning had begun. The first fish were seen July 24, but not until 
August 10 were any mutilated ones observed, and then only 3 out of 84 
examined showed any considerable mutilations. 
In marked contrast with this perfect condition of the fish as they 
arrive upon their spawning ground is that observed toward the close of 
the spawning season when scarcely a fish can be found whose fins are 
not badly frayed and upon whose body are not one or more large 
sores. 
The manner in which the mutilations are really received was readily 
determined by watching the fish while spawning. The spawning-beds 
are usually in very shallow water, often only a few inches deep. These 
beds are of fine granite gravel and sand. There is more or less definite 
pairing off of the fishes, and each pair usually does all its spawning 0B 
a certain area, which may be called the nest. The gravel and sa of 
this area are moved about and piled up somewhat in heaps or rows as 
the fish scoop out shallow depressions in the bed; this scooping OY 
moving of the gravel is done as the fish swims upstream over the bed 
with a rapid quivering motion of the body; during this act the body 1$ 
always inclined to one side and the gravel is chiefly pushed in the other- 
-direction ; after swimming across the nest in this way, the fish circles : 
around downstream and returns to the bed to repeat the process again 
and again, keeping it up for several days. During all this time the 
male follows closely behind the female, sometimes quivering and plow- 
ing through the sand and gravel in the same way and thus receiving 
mutilations of the same character. Often the back of the fish is tur? 
against the gravel and becomes worn. On each spawning-bed are usu- 
ally several supernumerary males, and among them and the paired males 
there is much chasing about and some fighting which results in still 
further mutilations. It may, therefore, be positively stated that the 
sores and mutilations seen on the redfish at the Idaho spawning-grow 
are practically all received after the spawning season begins (B. ie 
Everman in U.S. Fish Commission Bull. for 1896, Art. 2.) 
On the Occurrence of the genus Reithrodontomys in Vir- 
ginia.—On December 6, 1896, I trapped an adult male Harvest 
