Animal Flight, A Record of Observation

growth, development, physiology of respiration and digestion, his excellent summary of the principal investigations on the determination of age by means of the ootoliths, scales, oper- cular bones and vertebrae, and lastly, in a few pages relating directly to fish culture.A summary of the important literature is given under each heading, emphasis being laid quite naturally upon European publications.This feature together with a full bibliography will be especially helpful to American stu- dents.The consideration of all recent ex- perimentation and the judicious application of the principles set forth is a most commend- able characteristic of the whole work.