638 E. H. J. SCHUSTER. 



t\ pes. It is this intermediate structure whicli forms Brod- 

 mann's type 19. 



Extent and Boundaries. — The occipital type completely 

 suri'ounds the calcariue, tlie boundary between the one type 

 and the other being quite abrupt and definite. Very different 

 is the transition between the occipital and the inferior parietal 

 trmporal and posterior limbic types, into which it passes 

 anteriorly. This is so gradual that it is almost iinpossible to 

 say where the one ends and the other begins, and the boun- 

 dary is in consequence very difficult to describe. Under 

 these circumstances I do not attempt a verbal description, 

 but merely refer to the figures A, E, c, D. 



Temporal Type (fig*. 11). 



i- -r 1- -r -t t- + ■^- + + 

 ■t- + + + -i- -t -h + +. 



+ ^--(-+-t-+-■^+.-t- 



The essential features of the cortex covering the greater 

 part of the temporal lobe are shown m fig. 11, which is taken 

 from the middle temporal gyrus in its posterior half. Its 

 dei^th is here about 2 mm. 



The lamina zonalis extends to a depth of '2 mm. The 

 lamina granularis externa is closely packed with ceils and 

 fairly well separated from the underlying lamina pyramidalis. 

 The latter extends to a depth of rather more than half the 

 whole thickness of the cortex. The large pyramids (ui^j, 

 which reach a length of oO /.i or more, form a broad zone near 

 the inner border of the layer. 



The lamina granulans interna is exceptionally well 

 developed, and stretches from i"l mm. to I'o mm. frum the 

 surface. 



Beneath this layer the development of the cortex is poor in 

 comparison Avith the parts above, but the lamina ganglionaris 

 is fairly well developed, though its cells are slightly smaller 

 than those at iii6. A slightly clearer space separates it from 

 the lamina multiformis. 



