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                             THE WORKS

                                 OF

                     FRANCIS MAITLAND BALFOUR.

                             VOL. II.

                         Memorial Edition.




                            Cambridge:

               PRINTED BY C. J. CLAY, M.A. AND SON,
                     AT THE UNIVERSITY PRESS.




                         Memorial Edition.


                             THE WORKS

                                 OF

                     FRANCIS MAITLAND BALFOUR,

                        M.A., LL.D., F.R.S.,
                     FELLOW OF TRINITY COLLEGE,
      AND PROFESSOR OF ANIMAL MORPHOLOGY IN THE UNIVERSITY OF
                              CAMBRIDGE.


                             EDITED BY

                        M. FOSTER, F.R.S.,
      PROFESSOR OF PHYSIOLOGY IN THE UNIVERSITY OF CAMBRIDGE;

                                AND

                       ADAM SEDGWICK, M.A.,
        FELLOW AND LECTURER OF TRINITY COLLEGE, CAMBRIDGE.


                             VOL. II.

               A TREATISE ON COMPARATIVE EMBRYOLOGY.

                       Vol. I. Invertebrata.


                              London:
                         MACMILLAN AND CO.
                               1885




          [_The Right of Translation is reserved._]




                             PREFACE.


My aim in writing this work has been to give such an account of the
development of animal forms as may prove useful both to students and
to those engaged in embryological research. The present volume, save
in the introductory chapters, is limited to a description of the
development of the Invertebrata: the second and concluding volume will
deal with the Vertebrata, and with the special histories of the
several organs.

Since the work is,