Abstracted by B. F. Kingsbury, author 
Cornell University, Ithaca. 
The fundamental plan of the vertebrate brain. 
This paper examines conceptions of the fundamental plan of 
the brain and brain-plate from the standpoint of the occurrence 
and significance of the three sutures postulated by His (sutura 
dorsalis, anterior (terminalis, frontalis), neurochordalis). Chick 
and shark (Squalus acanthias) were the forms chosen for exami- 
nation. The study supports the analysis of the brain-plate pre- 
sented in an earlier paper by the author (Jour. Comp. Neur., vol. 
32, pp. 113-135), and confirms the interpretation of Johnston, a) 
that the brain-plate ends anteriorly (cephalically) with the 
terminal ridge embodying a potential chiasmatic ridge; b) that 
the two optic foveae (vesicles) are connected across the median 
plane by a primitive optic furrow which is also the primitive 
infundibulum (so-called). This relation but expresses the 
mechanics of growth. The approach was from the embryologic 
side, and it is indicated that the plan of the brain outlined and 
the early development of the brain are in full accord with the 
morphogenesis of the head as a whole. 
