110 PHYSIOLOGICAL SERIES. 



of the thalameneephalon, in the larger size of the optic 

 lobe-, and in the stronger development of the cerebellum. 

 Tin- olfactory bulbs arc separated from the hemispheres by 

 a shallow constriction and are fused together in the mid- 

 line. Behind this union the hemispheres are separate as 

 far hack as tho anterior commissure. Between their 

 posterior extremities there is, in the specimen, an oval 

 aperture in the roof of the thalamencephalon caused by 

 the removal of the paraphysis ; its hinder margin is 

 formed by the slightly protuberant ganglia habenulse and 

 their commissure. 



The optic lobes form the broadest part of the brain. 

 They are prominent oval bodies separated in the mid-line 

 liv a deep gutter. In front they diverge and expose a 

 part of the tectal commissure. Between this and the 

 thalamencephalon is a small crescentic pit at the base of 

 which lies the posterior commissure. A deep furrow sepa- 

 rates the optic lobes from the cerebellum. 



The medulla is somewhat shorter than in the Urodeles. 

 The epithelial and vascular roof of the rhomboid fossa has 

 l>een removed and mounted at the side to show its pleated 

 under surface. 



Ecker, Anat. of the Frog (Engl. trans.), 1889, p. 141. 



REPTILIA. 



Kdinger, Senckenberg. naturf. Gesell., Bd. xix. 1896 (Cere- 



I'rntn) ^ Bd. xxii. 1899 (ThalamencepJialon). 

 11;, Her, Morph. Jahrb., Bd. xxviii. 1900, p. 252. 



The Reptilian brain i- narrow and of considerable length, 

 with moderately de\<-lop.-d optic lobes and, except in swimming 

 I'MI-III-. \\ith insignificant cerebellum. The medulla ohlongala 



ihowi a strong longitudinal dnr-o-vcntnil curvature, convex below, 



In thi- cla the brain ditVer- inoM markedly From that of a lo\\er 

 (.rate in the great -tnictural advance of the cerebrum, 

 notably in the pre-mr.-. For the fir-t time in the Vertebrate 

 leriei, 'f :m undoubted cerebral cortex (fig. '60). The condition 

 of the pallium is of >pccial importance. It is not only much larger 

 than that of an Amphibian, but is also much more highly 



