Till OF L\ 



23 



.1 



the crystalline 11a, and tl [low 



an insect s< I: kit 



tin- cornea] lens like an ordinary 



38 lens to ■ -" the light, or form 



;iii image of a mo> ing body, eithei 

 win. ii. as tin' case may We. falls upon tin' 

 cone behind tin' lens. Tin- cone has 

 been fonnd by Mr. Patten t" in- rich in 

 extremely fine nerve-threads, the ends of 

 one of tin- fibres which unit.- to form tin' 

 optic nerve. Ii is thus highly sensitive. 

 The crystalline cone then, as Patten ob- 

 serves, is that part which is sensitive to 

 tin- light or perceives objects. The retina, 

 a ma-- of black pigment-cells enveloping 

 the ends "I' tin' cones and their stalk- 

 rods, and further comprising, as Elicls 

 thinks, all that part of the eye lying be- 

 tween the crystalline cones and true optic 

 nerve, is of use, especially in the com- 

 pound eye, in elaborating and combining 

 the sensations formed in th< -. Now 



the compound eye is simply, ><> to -peak. 

 a compound simple eye: not. a.- used to he 

 thought, a collection of sim, - joined 



together. The compound eye grows out 

 of, or is " differentiated. " from, a simple 

 : it is, as Patten says, "a modified 

 ocellus;" and this observer concludes that 

 the majority of compound eyes are adapt* 

 ception of inverted images formed by the 

 upon the crystalline cones." Of cours . •• the 



effect upon the insect*- mind is that . eobject. 



Experiments by Plateau on the simp nti] 



show quite decidedly that these creatu - 

 than distinguish light from darkness; tin ■■-■• out 



the form of objects, though some can • more 



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