434 INTRODUCTION. 



It should of course be borne in mind that these records and drawings were 

 made a number of years ago without any of the revision that is ordinarily in- 

 volved in the preparation of a paper for publication. It is not known what 

 changes might have been made in case the authors had carried the material 

 through to publication. 



It will be noticed that the records in this publication are remarkably full 

 and readable, as was characteristic of all of Professor Whitman's note making. 

 He was always painstaking and careful in recording his observations, which were 

 made with unusual attention to details. The details were also significant iii 

 his note making. 



In Fig. 2, Plate XXXII, an embryonic axis is indicated by the terms "an- 

 terior," "posterior," "right," and "left." Also in the explanatory material for 

 this plate and for others, references to this orientation occur. Professor Whitman 

 being uncertain about the evidence for the coincidence of the first plane of 

 cleavage with that of bilateral symmetry, suggested the problem to Miss Clapp.' 

 She obtained results with toad-fish eggs which caused Professor Whitman to 

 abandon the position, at least for some years. In conversation a few years 

 before his death, he indicated, however, that such an orientation of the early 

 cleavage stages should be looked for in other forms. 



This publication is issued with full recognition of the fact that others, 

 notably Kopsch - have more or less fully covered the same ground for other 

 fishes. However, no such beautiful and elaborate illustrations of such material 

 have been published, and they should be made available to students of 

 embryology. 



The original drawings and manuscript have been deposited in the Museum 

 of Comparative Zoology at Cambridge, Mass., where they will be accessible to 

 workers who may have occasion to examine them. 



1 Clapp, Cornelia M. Some points in the development of the Toad-fish {Balrachus tau).<Journ. 

 morph., 1891, 5, p. 494-501, fig. 1-3. — Relation of the axis of the embryo to the first cleavage plane. 

 < Biological lectures from the Marine biological laboratory, Woods Hole. Woods Hole, Mass., 1898. 

 Boston, 1899, p. 139-151, fig. 1-6. 



- Kopsch, Fr. Die cntstehung dcs dottersackentoblasts und die furchung bei Belone acus.< Internat. 

 monatsschr. anat. physiol., 1901, 18, p. 43-127, fig. 1-34. — Art, ort und zeit der entstehung des dot- 

 tersackentoblasts bei verschiedenen knochenfischarten.< Internat. monatsschr. anat. physiol., 1902, 

 20, p. 101-124, fig. 1-15. 



