CREATION BY EVOLUTION 



its beginnings, or rather of completing the imperfect story 

 told by fossils. 



The earliest stages in this history in the human embryo 

 are blurred out of all recognition, but if we examine the 

 earlier history of the tadpole or, still better, that of the newt, 

 a primitive amphibian, we can get a general idea of the 

 history of life from the beginning. The egg, as we have 

 seen, is a single cell in its essential structure, the same as a 

 whole group of single-celled animals termed the Protozoa. 

 This cell divides into many cells, which cohere together and 

 form a little hollow ball called the blastula. Similar little 

 balls, in which the cells have acquired green colouring mat- 

 ter, roll about in the waters of our ditches. The blastula 

 becomes converted into a hollow cup called the gastrula by 

 the pushing in of the cells at one end. The opening of the 

 cup is called the blastopore. This opening is retained 

 throughout life as the anus or vent of the animal, and above 

 the anus the tail grows out. The outer layer of the cup 

 forms the skin; the brain and the nervous system are at first 

 mere thickenings in this layer. The inner layer forms the 

 lining of the stomach; the rudimentary backbone is only 

 a ridge or folding of this inner skin along its upper surface. 

 The mouth is formed as a new opening in front; the gill 

 slits are clefts at the sides of the throat; the eyes grow out 

 as buds on the brain; the nose and ears are pits in the skin, 

 and behold! we have before us no longer a swimming cup 

 but the beginning of a tadpole, which is really a very primi- 

 tive type of iish. 



A study of the development of jointed animals (the 

 Arthropoda), of the MoUusca (clams, oysters, and snails), 

 and of the Echinodermata (starfish and sea-urchins) leads 

 us to similar startling and fascinating results. We find 

 that worms, arthropods, and mollusks arose from a common 



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