THERE has not yet been published, so far as the writer is aware, any work devoted to a complete account of the muscles of any single species of the Class Aves,-a work fully and practically illustrated, and one that would prove itself to be of service to those either engaged in the general study of the morphology of vertebrates, or to those special students who may be investigating the myology of birds. At the present time, when the study of the structure of animals is becoming far more general, as one of the most efficient aids to observation. and mental training, than it was so considered a number of years ago,-books of the class which your author has here endeavoured to produce come to be very useful. Birds stand among the most casily procurable subjects for the use of the demonstrator at the laboratory, or for the student to employ in his own researches at home as illustrative of certain parts of his course in biology. And it was to fill this so important a gap, as the lack of a suitable volume devoted to the muscular system of birds, that the writer undertook an exhaustive study of the muscles of the Raven (Corvus corax