464 B. F. KINGSBURY 
region (M). The line of secondary closure (of the neuropore, 
i.e., sutura terminalis) would be correspondingly increased in 
extent so that not only the optic chiasma, but the entire infun- 
dibular region would be thus included. A distinct advance was 
their recognition that the sulcus limitans could not be traced for- 
ward beyond the mammillary recess. 6) The second unique 
feature of their interpretation was the inclusion within the limits 
of the more cephalic portion of the alar plate of neural crest 
elements. As this does not closely concern the aspects con- 
sidered in this paper, no discussion will be given, nor is there in 
A of figures 1 and 2, which present their views, any diagrammatic 
expression of this side of their interpretation. 
My own interpretation is represented by D, figures 1 and 2. 
There it may be seen that the floor plate extends no farther for- 
ward than the fovea isthmi (cf. Kingsbury, ’20), whereas the 
medial cephalic limit of the brain plate would include the optic 
chiasma. The unique feature of the interpretation and the one 
on which in my opinion its value largely rests is that of a primary 
continuity across the middle plane of ‘nervous material’—alar 
and basilar plates—anterior to the fovea isthmi and floor plate, 
to both of which structures considerable morphological signifi- 
cance is believed to attach. In figure 1, D, the ‘prefoveal’ extent 
of the brain plate is indicated by heavy stippling. 
Thus each of these interpretations, although differing quite 
fundamentally, made I think a distinct advance toward an under- 
standing of the correct relations. My earlier paper outlines 
certain of the bearings of the interpretation offered by me. 
These it will be seen affect not alone or mainly the brain, but 
possess a broader bearing. The approach to the interpretation 
was from the embryological side rather than the neurological, 
and the writer’s interest has centered not so much in affording 
a satisfactory basis for analyzing the brain as determining the 
developmental pattern’ of the body. The early morphogenesis 
3 For anumber of years (cf. Kingsbury, ’13) I have recognized the importance of 
distinguishing Process and Pattern as two fundamental aspects of development as 
of life generally. Recently Child (’21) has likewise recognized the validity of 
the distinction, this time drawn between Pattern and Material, however. 
