/^ orb. 



fs erh. 



^ '■-. fs. rh. drc. 

 tuH.oi 



Fig. 32. — Lateral view of the brain of Orolestes inca, enlarged about 

 four times. After Obenchain (1925), The olfactory bulb {b.ol.) is very 

 large. The small cerebellum shows a large lobus medius {lob. m. cb.) 

 bounded behind by the fissura secunda {fs. s.). The cerebral cortex shows 

 two fissures. The orbital fissure {fs. orb.) cuts across the excitable motor 

 field, and the rhinic fissure {fs. rh.) separates the neopallium above from 

 the pyriform lobe {lob. pir.) below. The latter is separated from the 

 amygdala by a shallow amygdaloid fissure {fs. amg.). The olfactory tu- 

 bercle {tub. ol.) is a subcortical reflex center, separated from the cortex 

 by the large lateral olfactory tract {tr. ol. lat.), which in turn is bounded 

 above by the fissura endorhinalis {/s. erh.) and below by the fissura 

 rhinalis arcuata {fs. rh. arc). 



fs.pnod 



Fig. 2Z- — Median section of the brain of Orolestes. After Obenchain. 

 The very small neopallial cortex extends over upon the medial aspect as 

 far as the hippocampal fissure {fis. hip.), below which is hippocampal cor- 

 tex {hip. ant.). Still farther ventrally are the septum, or parolfactory area 

 {a. parol.)^ the olfactory tubercle {tub. ol.), dorsal or pallial commissure 

 {d), ventral or anterior commissure (y), massa intermedia of the thalamus 

 {m. i.), and farther back the tectum {tect.), or roof of the midbra-in. The 

 optic chiasma is at ch. 



