THE INTEGUMENT AND THE EXOSKELETON 89 



FIG. 23. Formation of friction ridges in pairs from rings formed by 

 the confluence of epidermic warts. [After Miss WHIPPLE.] 



All the figures are taken from Lemur macaco (semi-ape from Madagascar). 



(a) Detail of area below the interspace between index and medius. Here are 

 seen individual isolated warts w; groups of these forming rings g; fully formed 

 rings r; also the formation of ridges in pairs by the lengthening of rings in one 

 direction (best shown at the right) ; the single isolated ring enclosed by the ridges 

 of the pattern is also suggestive, (b) A portion of the interdigital pad. (c) Apical 

 pad. (d) Detail showing two methods of formation of three ridges from the rings. 



