296 



NERVOUS SYSTEM OF VERTEBRATES. 



of the lateral lobes, to the whole extent of which they are distrib- 

 uted. These are the olfactory lobes, including the equivalent of 

 the nucleus thaeniae of higher forms. The vertical groove in the 



Fig. 146. An oblique section through the inferior lobes and forebrain of Lam- 

 petra. Ill, median ventricle; a.o., olfactory lobe; d.p., postoptic decussation; e, epi- 

 striatum; ep., epiphysis; tr.e-s., neurites of epistriatum cells to striatum; tr. l-b., 

 tractus lobo-bulbaris; tr.o., tractus opticus; tr.o-h., tractus olfacto-habenularis; 

 tr.s-th., tractus strio-thalamicus; tr.th-sae., tractus thalamo-saccus; sac., saccus 

 vasculosus. 



lateral wall separating the olfactory lobes from the bulbs is the 

 only external indication of the olfactory tract, which is usually 

 recognizable externally in other vertebrates. A part of the olfac- 



