MORPHOLOGICAL STUDIES. 
163 
obtained according as one belongs to this that or the other 
school of embryologists. For myself, for the better compre- 
hension of my work on later stages, it was absolutely essential 
that a clear, precise, and uncontradictory account of the very 
first stages of the peripheral nervous system, and of the rela- 
tions of the latter to the central nervous system, should be 
worked out. It was necessary to attempt to do for the Verte- 
brate nervous system what Kleineuberg has done for that of 
the Annelid. Not that the following researches make any 
pretence to being an account comparable in minuteness of 
detail with Kleinenberg’s work, they are rather the beginnings 
of work on the matter; for there is still much to he done in 
the early development of both central and peripheral nervous 
systems of Vertebrates. 
According to Professor Wiedersheim’s opinion and my own, 
the most lasting results were likely to be obtained by drawing 
within the sphere of investigation as many types of Vertebrates 
as possible, and hence, although my original intention regarding 
this and other researches was to consider only Elasmobrancbs 
and Ganoids, in aid of which researches the Government Grant 
Committee of the Royal Society of London made a grant of 
money from the fund at their disposal, I nevertheless thought 
it in the interest of science to extend my observations to various 
classes of Vertebrates. So far I have had at my disposal embryos 
of (various genera) Elasmobranchs, Teleostei, of Amphibia, 
Reptiles, Birds, and Mammals. Researches on Ganoids 1 and one 
or two other types as yet unattainable, I hope in the course 
of the year to be able to carry out. For the moment in con- 
sequence of the time necessary for the preparation of the 
numerous indispensable drawings, I publish the results obtained 
on Elasmobranchii and Birds. 
1 The development in Ganoids conforms exactly to those in other types. 
