22 



INTKODUCTION. 



bristles on the soles of their feet, whicli give these creatures their 

 ■well-known power of running with great rapidity along vertical 

 walls or the ceiling of a room back downwards, without falKiig.'' 

 These hairs, like those described above, are nothing more than 

 specially developed casting hairs, for they originate in the same 



Fib. lO.-Stnictnre of tlie Gecko's foot ; a, from above ; 6, a toe with its clineinff ridses 



Mtos iStff d ^aSof'tti '• '"*^r. "' .^r"™ through fti?, 1Sfi"/^he 

 napsinaection, a, afewof these, magmfled, with their bristles • e foiirmwsnf hrisMp- 

 cells. muoh magmfied ; /. two separate bristle-cells, mor^ maSifie'd From C^SS 



way as those, and assist in the process of casting (fig. 8, a). 

 The clinging hairs are absent in the embryo of the Gtecko • they 

 do not appear till the first casting, and assist in causin'o- the 

 process ; this sufficiently proves that they were not primarily 

 destined to bo used as organs for clinging, but have acquired 



