370 THE BRAIN OF THE TIGER SALAMANDER 



The section pictures which follow are here reproduced from previous publications (with 

 minor alterations in some instances), and more complete descriptions will be found in the 

 references cited. 



Figures 87 to 91.- — Five transverse sections of the adult medulla oblongata. Method of 

 Wiegert. X 37. These are copies, respectively, of figures 5, 3, 2, and 1 of 19446 and figure 16 

 of 1936, drawn from the type specimen, no. IIC. 



Fig. 87. — Section taken immediately below the calamus scriptorius through the commis- 

 sural nucleus and the com. infima of Haller. 



Fig. 88. — Through the lower vagus region and the most anterior ventral rootlet of the first 

 spinal nerve. 



Fig. 89 .^At the level of the IX nerve roots. A rootlet of the \T nerve emerges in this sec- 

 tion. The two lateral-line roots of the vagus enter immediately rostrally of this level. 



Fig. 90. — Section taken immediately below the superficial origin of the V nerve roots, in- 

 cluding the posterior part of the motor V nucleus. 



Fig. 91. — Section through the cerebellum, auricle, and rostral end of the trigeminal teg- 

 mentum. 



Figure 92. — Transverse section immediately spinalward of the nucleus of the IV nerve. 

 X 37. Ventrally it passes through the posterior end of the infundibulum and dorsally through 

 the junction of superior and inferior colliculi. The Arabic numbers in parentheses refer to the 

 tegmental fascicles described in chapter xx. This is a copy of figure 14 of 1936, drawn from a 

 reduced silver preparation, method of Rogers. 



Figure 93. — Semidiagrammatic transverse section at the level of the III nerve roots. X 37. 

 Copied from figure 14 of 1942. The layers of the tectum and some of its afferent tracts are 

 shown on the left side and efferent tracts on the right. 



Figure 9^. — Section through the rostral border of the commissure of the tuberculum pos- 

 terius. X 37. Copy of figure 10 of 1936 and drawn from the same specimen as figure 92. 



Figures 95 to 100.- — These are obliquely transverse sections (ventral side inclined spinal- 

 ward), copied, with some alterations, from the paper of 1927, where full descriptions will be 

 found. X 25. They are from the brain of a recently metamorphosed adult from Colorado, pre- 

 pared by the Golgi method. The drawings are composite, the outlines and much of the detail 

 being derived from the specimen mentioned, supplemented by additional details selected from 

 20 other specimens cut in the transverse plane and stained by the methods of Golgi, Weigert, 

 and Cajal. 



Fig. 95. — Through the habenular commissure and the posterior border of the po.stoptic 

 commissure ('27, fig. 20). 



Fig. 96. — Through the rostral border of the chiasma ridge and the middle of the eminentia 

 thalami. By reason of the obliquity of the section, it passes rostrally of the habenulae ('27, 

 fig. 15). The cellular area marked p.v.ih. is the nucleus of the olfacto-habenular tract (p. 248). 



Fig. 97.- — Through the hippocampal commissure and the decussation of the lateral forebrain 

 bundles in the anterior commissure ("27, fig. 12). 



Fig. 98. — Immediately in front of the lamina terminalis. On the right side is a characteristic 

 impregnation of the neuropil of the corpus striatum. In the preparation drawn, only the 

 dendritic component of the neuropil is impregnated ("27, fig. 9). 



Fig. 99. — Section about 0.1 mm. anterior to the last, through the mid-septal region. The 

 head of the caudate nucleus is here at its maximum size. In the ventrolateral wall on the right 

 side the neuropil of the corpus striatum, in the preparation here drawn, has only the axonic 

 component impregnated (cf. fig. 108). These contorted and branched axons are interlaced with 

 the dendrites shown in figure 98, and the boundary of this area of dense neuropil is sharply 

 defined ('27, fig. 8). 



Fig. lOO.^Section through the middle of the olfactory bulb and the extreme anterior border 

 of the primordium hippocampi. It includes also the posterior border of the f. postolfactorius 

 ("27, fig. 4). 



