SPIDEES AND illTES. 239 



afTord cood characters by wliicli naturalists have 

 grouped them in genera. In the Cliibiona which ^ve 

 have been examining, they are placed in two nearly 

 straight transverse rows on the forehead ; but as this 

 surface is convex, it follows that the axis of every eye 

 points in a different direction from that of its fellows. 

 In Ejycira, on the other hand, — represented by our 

 great Garden Spider so commonly seen in the centre 



EVE OF SriDEE. 



of its perpendicular web, on shrubs and in corners of 

 our gardens, — the four middle eyes form a square, and 

 the two lateral ones on each side are placed in contact 

 with each other. 



It is interestino; to remark that their arrangement is 

 not arbitary, but is ancillary to the varying instincts 

 and wants of the different kinds. On this subject I 

 will quote to you what Professor Owen says : — " Tho 

 position of the four median ones is the most constant ; 

 they generally indicate a square or trapezium, and may 

 be compared with the median ocelli in hexapod insects. 

 Tlie two, or the two pairs of lateral ocelli may be com- 



