1909. The Expressions of Emotion in the Pigeons. I. The Blond Ring-Dove (Turtor risorius). Jour. Comp. Neurol. and Psychol., Vol. XIX, pp. 30-80.

Dawson, J.

1911. The Biology of Physa. Behavior Monographs, Vol. I, No. 4, pp. 1-120.

Behavior is related to the natural environment.

Davis, H. B.

1907. The Raccoon: A Study in Animal Intelligence. Amer. Jour. Psychol., Vol. XVIII, pp. 447-489.

Dean, B.

1892. The Physical and Biological Characteristics of the Natural Oyster Grounds of South Carolina. Bull. U. S. Fish Comm. for 1890, Vol. X, pp. 335-361.

Contains good illustrations of the oyster habitat.

Dimon, A. C.