AUTHOR’S ABSTRACT OF THIS PAPER ISSUED 
BY THE BIBLIOGRAPHIC SERVICE, APRIL 17 
THE EARLY DEVELOPMENT OF THE CEREBRAL 4 
HEMISPHERES IN AMBLYSTOMA 
H. SAXTON BURR 
Anatomical Laboratory of the Yale University School of Medicine 
TWENTY-SIX FIGURES 
Since the researches of His (’88, ’92, ’93) his original concept 
of the structure of the neural tube has been very generally ac- 
cepted. The work of subsequent investigators well known in the 
literature has established the main principles of the work of His 
beyond a reasonable doubt. In his early papers, however, he 
did not elaborate very fully the rostral relations of the longitu- 
dinal zones of the neural tube. It was his belief that these four 
primary columns meet at the ventral lip of the neuropore. On 
the basis of this assumption, the roof and the floor plates separate 
the neural tube into two independent lateral halves. It is evident, 
therefore, that the fate of the ventral lip of the neuropore becomes 
a matter of prime importance. This matter has been studied 
carefully by workers, among whom may be mentioned Johnston 
(05, 709) and Schulte and Tilney (15). In all the work that has 
been done, however, it has been tacitly assumed, as originally 
pointed out by His, that the floor plate terminated at the ventral 
lip of the neuropore. ‘The exceedingly interesting and suggestive 
paper of Kingsbury (’20) contains the first suggestion that this 
assumption is not altogether justified by the facts. During the 
progress of an investigation of the early development of the cere- 
bral hemispheres in Amblystoma it became evident that a more 
careful study of the rostral relations of the longitudinal zones of 
His was necessary. Several years ago Doctor Herrick suggested 
that a more detailed study of the early development of the cere- 
bral hemispheres might yield valuable data. The researches of 
Bindewald (’14), Crosby ('17), Heuser (’13), and others have 
shown in many forms the fundamental character of the telen- 
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