360 THE EVOLUTION OF MAN. 



become fins (pectoral and ventral) ; in Birds, wings and legs ; 

 in creeping animals, fore and hind legs ; in Apes and in Man, 

 arms and legs. All these parts arise from a first rudiment of 

 the same perfectly simple form, which grows secondarily from 

 the skin-layer (Figs. 119, 120). They always make their 

 appearance in the form of two small buds, which at first 

 resemble mere round knobs or plates. Gradually each of these 

 plates increases into a more considerable projection, in which 

 there is a more slender part, nearer the body of the embryo 

 and distinct from the outer, broader, thicker part. This later 

 portion is the rudiment of foot or of hand, while the former 

 is the rudiment of arm or of leg. Plates VI. and YII. show 

 how similar are the rudimentary limbs in very different 

 Vertebrates. 



A careful study and thoughtful comparison of the 

 embryos of Man and other Vertebrates in this stage of 

 development is very instructive, and reveals to the thought- 

 ful many profounder mysteries and weightier truths than 

 are to be found in the so-called • " revelations " of all the 

 ecclesiastical religions of the earth. Compare, for instance, 

 carefully and attentively the three consecutive stages of 

 development, represented in Plate VI. of the Fish (F), Sala- 

 mander (S), Tortoise (T), and Chick (C), and in Plate VII. the 

 corresponding embryos of the Hog (H), Calf ((7), Rabbit (R), 

 and of Man (if). In the first stage (upper row of Section 

 L), in which the head Avith the five brain-bladders, and 

 the gill-arches are indeed begun, though the limbs are still 

 entirely wanting, the embryos of all Vertebrates from Fish 

 to Man differ not at all, or only in non-essential points. In 

 the second stage (middle row of Section II.), in which the 

 limbs are indicated, differences begin to appear between the 



