22 



INTRODUCTION. 



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

 well-known power of running with great rapidity along vertical 

 walls or the ceiling of a room, back downwards, ^\ ithout falling.'' 

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

 specially developed casting hairs, for they originate in the same 



111 ijii «m • 



n Iff if 



r^ 



Fig. 10. — Stiticture of tlie Gecko's foot ; a, from above ; 6, a toe with its clinfring ridges, 

 from below, slightly magnified ; c, diafrraiii of section tlirough a toe, exliiblting the 

 rid'jes ill section ; rf, a few of these, magnifi'd, witli tiieii' bristles ; ^, four roivs of bristle- 

 cells, much magnified ; /, two separate bristlo-cells, more magnified. From Cartier. 



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

 The clinging hairs are absent in the embryo of the Gecko ; they 

 do not appear till the first casting, and assist in causing the 

 process ; this sufficiently proves that they were not primarily 

 destined to bo used as organs for clinging, but have acquii'ed 



