590 



THE AMERICAN NATURALIST [Vol. XLI 



other vertebrates. . . .is highly instructive and disclost-.s to the thought- 

 ful person deeper and weightier secrets than cire to he found in the 

 so-called "revelations" of all the religions of the eartli. Compare 

 attentively the successive stages of the chick, i)ig, rabbit, and man 

 shown in the accompanying figure. In the first stage (the upper row), 

 in which the head with the five cerebral vesicles and the gill arches are 

 clearly marked out but the limbs arc still wholly absent, the embryos 

 of all vertebrates from fishes to man differ from one another either 



which the limbs have begun to develop, distinctions between the 

 embryos of lower and higher vertebrates have begun to appear; yet 

 the human embryo even now is scarcely to be distinguished from those 

 of the higher mammals. . . .These are facts the significance of which 

 cannot be overestimated."* 



As drawings of embryos, the well known figures of Haeckel here 

 reproduced are totally valueless. The front limbs have been trans- 

 ferred to the neck, and the characteristic features by which any one 

 familiar with embryos can distinguish a pig from a rabbit have been 

 wholly overlooked. Although Parker declared that 'one diagram 

 would represent all,' his figure of the embryo mole could not possibly 

 be mistaken for a f)ig. Moreover tiie pig at this stage could be dis- 

 tinguished from the rabbit or man by its pancreas alon(^ The com- 



The ^,pherical yAk ..t tlic Ik n'> vo., the elongated vesicle of the sheep 

 (that of the piii iH'iiig (juite as I.mg but not so slender), the round 

 smootii vesicle ot the lahbit and the villous human vesicle are radically 

 (liHeietit troiii e;i( li other. Since these membranous structures are 



ot the embr\<) they must be regarded as expressions of differences 



Haerkel. ]]. Ant hr()i)ogenie. 3rd ed. Leipzig, W. Engelmann, 1877, 



