104 STUDY OF A HUMAN SPINA BIFIDA MONSTER WITH 



poral bones and the sella turcica it is drawn into numerous folds. On the inside 

 of the large encephalocele the smooth dural surface changes to a tissue composed 

 of mai\y blood-vessels, fibrin, and extravasated blood, as described in the beginning 

 of the paper. The falx cerebri lies well over on the left side in its anterior and 

 middle portions ; posteriorly it ends in a single fold about the center of the superior 

 margin of the occipital bone. The tentorium cerebelli is absent. The ventral 

 surface of the subdural space is pierced by two rows of cranial and spinal nerves. 

 These number 43 in all, 12 cranial and 31 spinal, the latter distributed as follows: 

 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal. Both the anterior 

 roots and the posterior roots with their ganglia are identified. In the cervical 

 and thoracic regions they are extremely crowded. 



The arrangement of the central nervous system is very complicated. The 

 cerebrum lies part above and part below the foramen magnum. The cerebellum lies 

 entirely below it. The medulla and cord lie bent and crumpled ventral to the other 

 structures below the foramen. The surface of that part of the cerebrum which 

 lies above the foramen shows definite fissure and sulcus formation. Below the 

 f ( iramen a large part of the contents of the encephaloceles consists of a hemorrhagic 

 mass and much of the surface of this is covered with caked blood, so that only in 

 a few places can typical cerebral surface markings be identified. Sections of these 

 regions, however, show definite though rather undifferentiated cortical lamination. 



From a brief study of sections of other parts of the left cerebrum, made by Dr. 

 Charles Bagley , the following points are determined : The cortical structure for the 

 most part is composed of a very wide granular zone, which is characteristic of the 

 early and undifferentiated stage of lamination. There is, however, a prominent verti- 

 cal fissure lying at the junction of the middle and posterior two-thirds of the cranial 

 dome, which can be identified as the central fissure of Rolando; the ventral termi- 

 nation of this fissure rests on the eminentia arcuata of the temporal bone. The 

 cortical tissue anterior to this fissure shows a definite lamination. There is a well- 

 defined first layer; a broad and poorly differentiated second layer; the third layer 

 is of medium width and is filled with small pyramidal cells; the fourth layer is 

 inconspicuous, suggesting the agranular motor type; while the fifth layer is rep- 

 resented by large pyramidal cells, probably Betz cells. These cells are at least 

 three times as large as any other cells which could be found in the cortex and it is 

 owing to their presence and to the very narrow granular layer that this area is identi- 

 fied as motor cortex. Immediately posterior to this fissure there is a sharp change 

 in lamination types. The large cells are lost and the fifth layer is represented by 

 definitely shaped pyramidal cells of not more than one-third the size of those cells 

 designated as Betz cells. Above this layer there is present a very heavy granular 

 layer which is quite a contrast to the narrow granular layer of the area just de- 

 scribed. It may be said, therefore, with a fair degree of certainty, that the tissue 

 posterior to the fissure represents sensory cortex. 



From the rather limited amount of material studied the only other localization 

 that could be determined is that the cortical tissue pushed down on the side of the 

 wedge-shaped mass 1 11" in the model) represents subiculum. Here, passing from a 

 cortex ,of quite deep extent, it becomes suddenly shallow and consists of a typical 



