468 B. F. KINGSBURY 
Johnston (09), it may be recalled, gave evidence that, a) the 
retinal foveae (evaginations) were connected across the median 
plane by a furrow, the same which His might have termed the 
‘basilar furrow’ as the internal counterpart of his ‘Basilarleiste.’ 
This furrow Johnston concluded might persist as a postoptic 
recess, while the infundibulum was a secondary development. 
The optic chiasma he found occupied the cephalic border of the 
brain plate (cf. Kingsbury, ’20, p. 122). 
A merely cursory inspection of figures 9 to 18 of plate 1 and 
the corresponding median plane reconstructions of plate 2 (figs. 
18 to 22) suffices to confirm the conclusions of Johnston on the 
first point, since it is evident that his first transverse furrow on 
the brain plate is continuous with the retinal foveae and later 
with the optic vesicles, and therefore well deserves the name of 
‘primitive optic furrow.’ It would seem to me, however, that it 
also constitutes the primitive infundibulum‘ and is in fact at one 
and the same time primitive optic furrow and primitive infun- 
dibular furrow. While it is probable that in the unequal growth 
of the region it becomes, as Johnston affirms, the relatively in- 
significant postoptic recess, I have not noted any indications 
that such is the case, doubtless because sufficiently late stages 
have not been examined. Although it differentiates relatively 
late, the same comparison of figures indicated quite clearly that 
the chiasma is included within the extent of the brain plate. 
In the later stages medial sections (figs. 23 to 26) alone are not 
conclusive, but, interpreted from the relations of the optic stalk 
in the more lateral sections, they sustain Johnston’s conclusions 
in this regard also. 
4 Johnston’s contention that the definitive infundibulm (i.e., depression leading 
to and into the cavity of the pars nervosa of the hypophysis) is a secondary or later 
development is of course entirely correct. Embryologists have, however, so 
generally applied to this primitive recess the term infundibulum that perhaps for 
a time at least the designation may be retained, but distinguished as the ‘primi- 
tive infundibulum’ or ‘primitive infundibular recess.’ It should be appreciated 
that it is but an expression of the mechanics of growth of brain and head in their 
early morphogenesis. The term ‘hypothalamus’ seems to the writer to apply 
more exactly to the topography of the wall and thus leave a need for an additional 
and supplementary term. The question of the nomenclature of this portion of the 
diencephalic floor is discussed by Tilney (’15). 
