204 THE CEREBRUM. 



is ill defined. (3) A layer of medium-sized pyramids placed at 

 various angles occupies the place of the third, fourth, fifth and 

 sixth layers of typical cortex. (4) The layer of spindle cells. 

 In the spindle-cell layer are found the remarkable chromophilous 

 cells. They are triangular or pyramidal in shape and have greater 

 affinity for stains than the cells of any other part of the cerebral 

 cortex. 



The claustrum (Figs. 31 and 42) is a sheet of peculiar gray 

 substance which, according to Meynert, may be classed as cortical. 

 In structure it resembles the seventh layer of typical cortex, 

 being made up of fusiform cell-bodies. The claustrum is a 

 vertical antero-posterior sheet placed medial to the island, and 

 lateral to the external capsule. The surface in contact with the 

 external capsule is smooth, but the external surface is convoluted 

 to coincide with the gyri insulae. At its lower border it joins the 

 lentiform nucleus. 



II. GANGLIONAR GRAY MATTER. 



The substantia grisea ganglionaris is found in the great ganglia 

 which, in their situation and relations, have already been con- 

 sidered. They should be re-studied in this connection. They 

 are as follows: 



1. In the hemisphere: 



The corpus striatum, composed of the caudate and the 

 le"ntiform nucleus. 



2. In the inter-brain: 



The thalamus, lateral and medial geniculate bodies, nucleus 

 hypothalamicus (Luysi) and red nucleus. 



3. In the mid-brain: 



The superior and inferior quadrigeminal colliculi, the sub- 

 stantia nigra, and the nucleus lateralis superior in the 

 tegmentum. 



The corpus striatum (Figs. 64, 31 and 66) is an ovoid mass 

 of reddish-gray matter containing pigmented multipolar cell- 

 bodies of various sizes, those of large size being more numerous 

 in the nucleus lentiformis than in the nucleus caudatus. The 



