HISTORY OF THE OPHIDIAN EYE 



633 



The largest snakes — including the monster of them all, the 35-foot regal 

 python — are in the most 'primitive' family, the Boidae. 



If big monitors had simply 'become' big snakes, there would have been 

 no need whatever for such a rebuilding of the eye as has occurred in the 



Introconjunctival spaca 



-Sclera ( fibrous ) 



^Choriold 



!tino(wlth 



lique double 



cones) 



No cone oil droplets 



No epichorioidal lymph spaces 



Fig. 183 — Snake eye, diagrammatic, for comparison with that of lizard. 

 (The dotted arrow shows the direction of application of the force of accommodation). 



Ophidia. The modern snakes would have done just as well with unmod- 

 ified lacertilian eyes as have the various imitation snakes — the legless 

 above-ground lizards such as our Ophisaurus ventralis and the European 

 Anguis fragilis. Earlier in this volume it was noted that the universal 

 presence of the spectacle, in snakes of all habits and habitats, could only 

 mean that the first snakes so lived as to require a spectacle : they were 



