ENCEPHALOCELES AND OTHER ABNORMALITIES. 105 



first-zone layer containing few cells and a well-marked second layer with only a 

 narrow zone of undifferentiated cortex beneath it. No calcarine type of cortex was 

 identified, but the occipital lobe was probably included in the hemorrhagic mass 

 in the encephaloceles, which was in such a bad state of preservation that no sections 

 could be made. 



On the right side of the cerebrum the fissure corresponding to the left central 

 fissure of Rolando is situated slightly more anteriorly than on the left. The frontal 

 lobes thus occupy most of the shallow vault and rest in the anterior and in the 

 medial cranial fossae as well, which latter normally hold the temporal lobes. The 

 sulci of the frontal lobes are changed considerably from their normal positions. 

 The anterior ends of the superior medial and inferior frontal sulci are bent very 

 sharply downward. They are all situated nearer the base of the brain than usual, 

 as if the tissue had been pulled down on the lateral surfaces. Thus the superior 

 sulci lie halfway down the sides, with the medial and inferior sulci correspondingly 

 below them. With the exception of part of the parietal lobes on each side, the rest 

 of the cerebrum lies below the foramen magnum. The left-sided position of the 

 falx cerebri allows more room in the cranial cavity proper for the right cerebral 

 hemisphere than for the left. This results in a larger portion of the parietal lobe 

 on the right side lying above the foramen magnum than on the left side, and cor- 

 respondingly a larger amount of parietal surface lying below the foramen on the 

 left than on the right side. 



The cerebral tissue which lies below the foramen is partly contained in the 

 large bony pocket formed by the upper vertebral plate, and partly in the middle 

 and left encephalocele. Sulci are present over its surface, but are so distorted 

 that they can not be identified, nor can the identity of the lobes be determined. 

 In the contents of the middle and left sacs one can easily discern cerebral gyri, 

 and the general histological structure of these is similar to that of the cerebral tissue 

 situated above the foramen. In the middle sac there is a large amount of clot. The 

 cerebral tissue which lies in the cervical and thoracic vertebral pocket is pressed out 

 into a thin shell, and lies next the dura, being limited anteriorly by the emerging 

 cranial nerves. On the sides and back it is continuous with the cerebral tissue 

 lying in the cranial vault and with that pressed out into the encephaloceles. 



In the interior of the brain the optic thalami may be identified, lying above the 

 foramen. A small space representing the third ventricle, greatly compressed, lies 

 between the thalami. C'horoid plexus tissue is present. Its relations, however, 

 to the adjoining structures could not be determined. The cerebral peduncles may 

 be seen as flattened bundles lying central to the shell of the cerebral cortex. The 

 optic nerves are present. The hypophysis lies embedded in the well-formed sella 

 turcica. No other structures in this region or below can be identified until, in the 

 pocket of bone formed by the thoracic vertebrae, the inverted floor of the fourth 

 ventricle is recognized. 



The midbrain with attached fourth nerves, the colliculi, and the aqueduct of 

 Sylvius were not identified. The fourth nerves, however, were found at their 

 dural exit. Judging from the position of the fourth ventricle floor, a sharp bend 



