Arnold 1937. Primitive Area, Strawberry Canyon, Berkeley, Alameda Co., Calif. Dec. 17, will use hereafter. Yesterday I marked two mice: - 1 Pero. maniculatus and 1 Pero. t. gilberti. I gave each the #1 mark (see chart for marking). Today I marked two Peromyscus m. g. and three P. t. g.: using the system whereby I gave each species separate numbers. Hereafter, however there will be one set of serial numbers for all the mammals. This will avoid confusion. The following are the mammals marked today: 3 Hd. & Peromyscus maniculatus Caught in ferns on steps. The seventh step - 1st group of steps from the west fence - when freed it went uphill. - Given #2 marking. Returned Dec. 19 Ret. Dead on Almost frozen: Dec. 17 Liberated after warming. 4 Hd. & Peromyscus truei gilberti Caught beneath elderberry tree by path 50 yds west #3 Ran down hill when released. - Given #2 marking 5 Hd. & Peromyscus truei g. Caught 20 ft. west #4