298 



ANATOMY OF VERTEBRATES. 



Blenr, 



Anguilla, Cyclopteri 



19G 



G aster osteus, Eperlanus, Coi- 

 tus, Tricjla, Amblyopsis, 

 Echeneis, the Ganoidei, 

 and Lepidosiren. 



As the crus of the 

 rhinencephalon is formed 

 not only of fibres con- 

 tinued from the f)rosen- 

 cephalon, but also, and 

 in some fishes chiefly, of 

 distinct white and grey 



« T^ i n ifflt flPji S™* ^!^ tracts, traceable along the 



K SaSki ^InwMH^ base of the mesencepha- 



^S^hnf' nl % .VmF 'Hnk ion, in part as far back as 



the prcpyramidal bodies, 

 so the origin of the olfac- 

 tory nerve has been de- 

 scribed as characterised 

 3iJL twK \!^ liH Wm '^y ^^"'^ complexity and 



JiUiIvIm fHB |B| extent; and it is true 



^/■H v^Aiw^fJ^nn Wmak \\i&± in some instances 



(e. g. in the Perch), 

 here the rhinence- 

 1 halon, figs. 180—182, 

 is in contact with the 

 1 rosencephalon, ib. c, a 

 nail portion of the true 

 [factory nerve may be 

 listinctly traced back- 

 ard as far as the mesen- 

 sjihalon : just as we find 

 I some fishes (e. g. 

 VW H C'^HB* '' II iimUIW "^turgeon) a portion of 



7 I » \. ^E n fjlilR '^"^ optic nerve traceable 



'. n m M «» t\\. JiUlHi 5 far back as the cere- 



bellum, and in the Eel 

 to the hypoaria, and not 

 exclusively terminating 

 in the optic lobe. IMost 

 of the characteristics of 

 origin and course attri- 

 buted in works of Comparative Anatomy to the olfactory nerves 

 are to be understood of the 'crura rhincnceiihali.' In the 



Uraiu ,111(1 ccrfl.ni] nr. 



