344 



THE BRAIN OF THE TIGER SALAMANDER 



Figures 37, 38, and 39. — These semidiagrammatic sketches show some details of the 

 medulla oblongata from an advanced larva. The sections are obliquely horizontal, with the 

 right side and the anterior end more dorsal. X 30. The series contains 27 thick Golgi sections, 

 numbered from dorsal to ventral surfaces, and the data here assembled are selected from sec- 

 tions 11-24. The outlines of sections 13, 17, and 20 are drawn, and upon these there are 

 sketched some details from these and neighboring sections. The impregnation is scanty on a 



37 



38 



clear ground, with long courses of individual fibers clearly shown. There is no impregnation of 

 the lemniscus systems and but little of fibers descending from above the isthmus, so that the 

 intrinsic bulbar structures impregnated are well defined. In figures 37 and 38 the boundary be- 

 tween gray and white layers is marked by a broken line; in figure 39 the gray of the inter- 

 peduncular nucleus is stippled. 



Fig. 37. — On the left side this section cuts through the base of the auricle and the floor of 

 the lateral recess. The right side is more dorsal and includes the superior visceral-gustatory 

 nucleus and its neuropil, within which are collaterals from tr. tecto-bulbaris rectus (p. 225). 

 On the left side, V root fibers arborize in the ventral part of the isthmic neuropil, and some of 

 them continue into the cerebellar commissure. Almost the entire course of the postfacial f . 

 solitarius is projected from several sections. 



