130 THE BRAIN OF THE TIGER SALAMANDER 



nated) pass downward as internal arcuate fibers to the spinal cord 

 and medulla oblongata, some uncrossed and some decussating in the 

 ventral commissure. Other crossed fibers join the tractus spino- 

 cerebellaris and the spinal lemniscus (fig. 3). The secondary fibers 

 from the commissural nucleus are unmyelinated. Some of them are 

 internal arcuates, which distribute to neighboring parts of the spinal 

 cord and medulla oblongata of the same and of the opposite side; 

 and some pass directly laterally to the pial surface, where they turn 

 rostrad in tr. visceralis ascendens (fig. 8; '44&, figs. 10, 11, 12, tr.v.a.) 

 to reach the superior visceral nucleus in the isthmus and the ventro- 

 lateral neuropil of the peduncle. Some further details about the con- 

 nections of these nuclei are in the next two chapters. 



The region of the calamus scriptorius is evidently an important 

 center of correlation and integration of general somatic and visceral- 

 gustatory sensibility of the entire body, with efferent discharge di- 

 rectly to the motor zone and also to higher centers of sensory correla- 

 tion. Here root fibers of cutaneous and deep sensibility from the 

 head, trunk, and limbs; of vestibular and lateral-line sensibility; and 

 of gustatory and visceral sensibility converge into a common pool, 

 which is the first integrating center of these functional systems to 

 mature in ontogeny. 



