OF DENISOX UNIVERSITY. 69 



nective tissue fibrils due to the structure just described. A bundle 

 passing from above nearly parallel to the median line and obliquely 

 caudad, seems to be Meynert's bundle, as seen in longitudinal sections. 



Sections caudad (Fig. 4,) indicate the rudiment of the ventricle 

 of the optic lobes so prominent in reptilia, etc. The fibre tract above 

 this may be distinguished as the commissure of the optic lobes or 

 simply optic commissure. 



Sections posterior to the nates and therefore passing through the 

 testes near their base and nearly parallel to the base are. because of their 

 position, at right angles to the nates. 



(Section immediately following Fig. 5, Plate IX. VI-r-25.) The 

 outline of the section is approximately semi-circular, the upi)er surface 

 being truncate. The aqueduct which lies near the dorsal asi)ect is 

 rhombic with the angles produced in the horizontal and vertical planes. 

 The bridge is abruptly separated from the peduncular portion, except 

 ventrally. where its fibres separate into fascicles inter-digitating with 

 each other and leaving intervals which are filled with densely nucleated 

 gray matter. The dorsal half of the section is composed of nearly 

 homogeneous, finely nucleated gray matter, in which are no well-lim- 

 ited nuclei-portion of testes. The latero-dorsal angles are occui)ied 

 with obscure and ill-defined longitudinal tracts. The lateral aspects of 

 the dorsal half are occupied by arching fibre tracts passing ventrad 

 which seem with little doubt to be backward continuation of fibres 

 descending from the nates. The tract disappears by i)assing caudad 

 out of the section at a point dorsad to a well defined nucleus lying just 

 laterad to the ventral pyramids, which latter here form strong bundles 

 with oval sections. The nucleus just mentioned (pons nucleus,) is 

 similar to the gray matter filling the interspaces between the pons 

 fascicles. 



Upon the dorsal aspect of the ventral pyramids is another small 

 nucleus, having a narrow encircling band of gray, with the longer 

 axes ot the cells parallel to the plane of section and at right angles to 

 the fibres. 



Above this nucleus is a small circular cluster on either side near 

 the median line, consisting of larger multipolar cells. Still dorsad and 

 in the ventral aspect of the dorsal longitudinal fascicle, is a larger nu- 

 cleus on either side, likewise circular in outline and densely i)acked 

 with cells of median size and irregular contours. The area imme- 

 diately surrounding the acjueduct is homogeneous and sparsely si)rink- 



