ENCEPHALON OF REPTILES. 



291 



188 



functions of organic life. In the active state of the summer 

 season, such mutilation is followed by death in one or two hours, 



rarely more. 1 



In serpents, the cerebellum, fig. 188, c, expands into a depressed 

 semicircular lobe directed backward from the confluence of the 

 restiform crura and overlapping the major part of the fourth 

 ventricle, which appears as a short median fissure. The optic 

 lobes, ib. b, now expanded 

 to the breadth of the cere- 

 bellum, show both a longi- 

 tudinal and a transverse 

 fissure, the latter crossing 

 near the hinder border, and 

 giving to this part of the 

 brain a close resemblance 

 to its homologue the ' bige- 

 minal bodies * in Mammals. 

 The optic lobes are hollow : 

 the cerebral crura show 

 slight enlargements, like 

 optic thalami, anterior to 

 the optic lobes, before ex- 

 panding into the hemi- 

 spheres. These are pressed 

 into close contact medially, 

 and compose a prosence- 

 phalon nearly as broad as 



Ion":, and double the 



o 7 



breadth and length of the 

 mesencephalon. The outer 

 surface of the hemispheres 

 is smooth, composed of a 

 thin layer of vascular or 

 grey iieurine* Into their 

 cavity or ventricle a ( cor- 

 pus striatum' projects from 

 the under and outer side ; beneath or mesiad of which is a minor 

 prominence. The septum, formed by the thin mesial wall of 

 each hemisphere, is perforated for the passage of a ' chorokl 

 plexus.' The ventricles are continued forward into the olfactory 

 lobes, fig* 188, i ; each is marked off by an oblique fissure from 

 the fore part of the hemisphere, which it equals in breadth ; 



1 cci. 



u 2 



ffl 



Braiii aiid Xerves of the Boa Constrictor. LIT. 



