292 Dynamic Theory. 



occasional human cases of reversion to hands and feet, having six digits. 

 No mammal has six digits, so the reversion must be to a type below the 

 mammals. Ought we not to class the curious de\elopment of the 

 Groat-sucker's fine comb as a progressive one ? (Fig. 121.) 



It is said that Bucephalus, the celebrated war-horse of Alexander the 

 Great, in addition to having a head like an "ox," by which he got his 

 name, was a three-toed animal. If so, his feet reverted to the type of 

 those of the horse of Miocene Times. ( See fig. 73. ) 



FIG. 122. 



FIG 123. 



FIG. 122. Supernumerary Toe. (After Annandale. ) 

 FIG. 123. Supernumerary Thumb. ( 



FIG. 124. Webbed fingers, 

 ( After Reeves. ) 

 FIG. 125. Monstrous hand. 



(After Annandale.) 

 Arrested development 



(After Annandale.') 



FIG. 125. 



There are many sorts of monstrosities which probably must be re- 

 ferred to a tendency to crystal-variation. There are monsters in which 

 some part of the body is wanting or is developed too much. There are 

 others in which parts which should be separated are coalesced ; others 

 in which parts are separated by a fissure which ought to be joined to- 

 gether; others still in which normal openings never are opened. This 



