656 'Journal of Comparative Neurology and Psychology. 



the mid. temp, couvolutiou. These are to he seeu in the dissection, 

 Fig. 1. Both this and the posterior descending branch are closely 

 associated posteriorly with the fasc. trans, occ, some of which enters 

 the mid. temp, convolutions with some of the shorter transverse 

 vertical association fibers belonging to the angular gyrus and the 

 anterior part of the occipital lobe. The fasc. trans, occ. is very strik- 

 ing in its appearance, size, and complete isolation from the longitu- 

 dinal fibers under it, among which is the fasciculus occipito-frontalis 

 inferior. It is easily dissected as a broad vertical bundle about half 

 an inch in depth and extending in width from the pole of the occipital 

 lobe to the arcuate fibers. In Fig. 1, 2, and 3 the middle part 

 of it is removed to show more completely the fasc. occ. front, inferior. 

 The fibers are at right angles to the fibers of the fasciculus occipito- 

 frontalis inferior, and to the optic radiation. They are separated 

 from the fasciculus by a thin layer of neuroglia which is apparent 

 to the naked eye. It is nearly 1 mm. in depth. There is no difficulty 

 in recognizing this soft spongy substance in dissecting this region, and 

 when we meet it we know that the next structure to be revealed is 

 the fasciculus occipito-frontalis inferior intermixing with the optic 

 radiation and the fasc. occ. temp. 



The fasciculus occipito-frontalis inferior is pierced at its lower 

 edge by fibers from the tapetum, as is shown in Fig. 1. Excepting 

 this, there is little intercrossing of transverse fibers with it along 

 the greater part of its course, which is well shown in Figs. 1 

 and 2 at various intervals peeping from behind other structures or 

 exposed throughout the whole of its course as seen in Fig. 4. 



In all these dissections a great part of the whole of the temporal 

 lobe, and some of each of the other lobes, are removed and the 

 brain, as dissected, presents a new and unusual picture which may 

 not be readily understood at first glance. I have supplemented these 

 dissections with cross sections of a brain cut as indicated at A, B, C 

 (Fig. 8). The position of the fasciculus in each of the three sec- 

 tions (Figs. 5, 6, and Y) with its chief relations at those points, 

 is indicated. There is also a diagrammatic representation of its 

 course shown in the outline drawing. Fig. S. 



