102 



Journal of Comparative Neurology. 



tance in the cord or brain to end in other segments. Further, 

 an examination of the central arrangement of the olfactory ap- 

 paratus shows that the chief characteristics of central sensory- 

 nuclei and tracts are wanting and that the olfactory apparatus 

 presents a quite peculiar arrangement. 



The end-nucleus of the olfactory nerve is the olfactory 

 lobe, situated in the morphologically dorsal part of the fore 

 brain near its extreme rostral end. In this there are found cells 

 of the I and II types which in the lower vertebrates have not 

 reached any considerable degree of specialization. Their neu- 

 rites are sent to several nuclei which are also found in the 

 morphologically dorsal part of the fore brain (epistriatum, area 

 olfactoria, and nucleus thaenise). The fibers are partly direct, 

 partly crossed, the decussation taking place in the anterior com- 

 missure, or in a separate moitie of the same, the olfactory com- 



P*i- ■?• — Diagram of the central olfactory apparatus, a. o.— area olfac- 

 toria ; b. M. — bundle of Meynert; c. «.— corpus interpedunculare and other 

 nuclei of the bundles of Meynert ; <r.— epistriatum ; g. A.— ganglion habenulse; 

 /.I. — lobus inferior; l.o. — lobus olfactorius ; i1/.— motor centers ; j.— striatum ; 

 J. m. f. — somatic motor fasciculus ; th. — thalamus. 



