414 'Journal of Comparative Neurology and Psychology. 



into the formatio reticularis. It probably is the path of conduction 

 between the visceral sensory centers of the oblongata and the 

 corresponding areas of the spinal cord. 



The commissura infiina of the Angiiillid<^. — The brain of the eel 

 is strikingly selachian in aspect and by reason of its extreme elon- 

 gation presents some features of the oblongata more clearly than 

 any other type. My material consists of two series of the brain of 

 Conger cut transversely and stained by Weigert's method, two 

 of Anguilla cut transversely and stained by Delafield's and 

 Mallory's hematoxylin respectively and two of Anguilla cut 

 horizonally and stained by Delafield's and Weigert's h.iema- 

 toxylin respectively. 



The somatic sensory centers of these brains are very highly 

 developed, the visceral sensory centers moderately. The vagal 

 lobe is greatly elongated; it receives in front the visceral sensory 

 root of the facial nerve, the sensory IX root about midway and the 

 sensory X roots at the caudal end, beyond which it passes directly 

 into the visceral commissural nucleus. There is no specially differen- 

 tiated facial lobe. The ascending secondary gustatory tract arises 

 from the whole extent of the vagal lobe in the typical manner. From 

 the cephalic or facial end of the lobe a descending tract appears to 

 pass back ventrally of the spinal V tract into the dorso-lateral 

 fasciculus for the funicular nucleus and spinal cord, like the de- 

 scending secondary tract from the facial lobe of Ameiurus; but 

 the sections do not make the relations perfectly plain. 



The vagal lobes at their caudal ends fuse and from the point of 

 fusion the visceral commissural nucleus extends far backwards as 

 a compact mass of dense neuropil containing few medullated 

 fibers, many cells and unmedullated tracts running in various 

 directions, many of which cross the median line. Some unmed- 

 ullated vagus terminals probably reach this commissure, though 

 the Weigert sections do not permit a demonstration of this. 

 Strong unmedullated tracts pass from the whole length of this 

 nucleus into the formatio reticularis of the same side (figs. 6, 7, 

 8). This visceral nucleus extends far caudad, diminishing in size 

 and sharply marked off structurally from the adjacent somatic 

 centers. The nucleus ambiguus accompanies its lower border for 

 some distance and can be followed back as far as the level of the 

 second spinal nerve (figs. 6 to 10). With the enlargement of the 

 funicular nuclei in this region the visceral area shrinks to a mere 



