126 
Str. moleculare as Goner!) and Hit have done; but it is quite un- 
justifiable to speak of such a Fascia dentata as a convolution as 
the former does, or as something quite apart from the cortex and 
possibly a development of the thalamencephalon?), as the latter 
does. If the term Fascia dentata be used in this sense it must be 
clearly understood that it is merely the extremely modified 
superficial part of a region of cortex whose deeper 
part (layer of polymorphous cells) contributes to the formation 
of the Nucleus fasciae dentatae. 
Thus the opinion of SCHWALBE and others that the Fascia den- 
tata and its nucleus form one convolution is supported by the clear 
evidence which an examination of the monotreme brain brings to light; 
but SCHWALBE, as well as Ramon y CaJAt, fails to point out that the 
essential factor in the morphogenesis of the region is the unequal growth 
of the different layers of the convolution. 
The view of SALA and STRASSER, who regard the hippocampal 
formation as an interlocking of two U-shaped convolutions, is also at 
fault. As I have already insisted, the two U’s are of quite different 
significance, and one of them is not a convolution. 
The Nucleus fasciae dentatae is largely composed of the deeper 
part (layer of polymorphous cells) of the convolution from which the 
Fascia dentata sprung. It may also contain a few of the marginal 
cells of the layer of pyramidal cells. 
In conclusion it may be pointed out that appearances in certain 
sections would lead one to question the statement that the layer of 
pyramids is serially homologous with the Stratum granulosum only 
(as Fig. 2 would suggest). It is quite possible that some cells of the 
layer of polymorphous cells in the region of the Fascia dentata are 
also serially homologous with the layer of pyramids of the cornu 
Ammonis. : 
Sydney, March 3, 1896. 
1) loc. eit. 
2) Thus on page 397 (loc. cit.) Hitt speaks of the F.d. as “a band 
of grey matter added to the cortex” and which developes from the wall 
of the forebrain — whether primary or secondary he is doubtful. 
