88 PHYSIOLOGICAL SERIES. 



tin- other hand the olfactory region, whose great development 

 t onus one of the mo-t >triking features of the Elasmobranch 

 brain, i- peculiarly feeble in the Teleostea. The olfactory bulbs 

 are small, either ..,- ile uj.on the cerebrum or connected with it 

 by long peduncles, and the cerebrum itself is represented by a 

 pair of rounded basal ganglia roofed over by an epithelial non- 

 nervou> pallium (fig. -21). 



The thalamencephalon shows essentially the same features in 

 both group-, although much comi)ressed antero-posteriorly in 

 the Tele, -tea. The cerebellum is large, except in some sluggish 

 bottom lUh (e.g., Lophius, Cyclopterus), but is usually solid 

 and not hollow as in the Elasmobranchs. Its anterior parts 



Fig. 24. 

 BL.CORR 



... EPEND. 





 BL.V. 



-CORP.STR. 



Section of Pallium imd Corpus striatum of a Gold-fish. 



also are strongly developed, and protrude forward beneath the 

 tectum opticum into the cavity of the optic lobes, forming the 

 highly charaeti-riitic Teleostea n valvula cerebelli. The medulla 

 i- in moM OMM much concentrated and often shows remarkably 



\vell-<levelope<l facial and vagal lobes. The basal ganglia of the 

 cerebrtnii have much the siim- minute structure as in Elasmo- 

 braneh- ; they are united by conimiViiral si rands (c. interlobu- 

 l;iri-) that occupy a tbickening of the floor of the common 

 \.-ntricl.-. The-.- ..mmi^ure- are derived partly from the 

 olfactory areas and partly from the striatum. Their relation 

 to the anterior r<mmii>~iirc of Mammal* is doubtful. 



The thalamencephalon, in minute structure and arrange- 

 ment of trael- and nuclei, is approximately similar to that in 

 JMohraneh-. th-- n-i el,ro-h\ pot halainie tractfl b.-ing, ho\ve\ei. 



