174 THE STORY OF LIFE IN THE SEAS. 



the gills in Fishes, indicates that their ancestors 

 in remote periods lived in water and not on dry 

 land. 



Again the presence of rudimentary eyes in the 

 Mole and other subterranean animals indicates 

 that at one time its ancestors must have lived in 

 the light of the day. The characters of the 

 embryos of some of the land and fresh- water 

 Snails proves that they are derived from ancestors 

 that lived in the sea. 



When we collect together all the evidence of 

 this kind and place it side by side with the facts 

 revealed to us by Geology, the irresistible con- 

 clusion is arrived at that all animals are originally 

 derived from ancestors that lived in the sea. 

 And when we consult the botanists and find 

 that they are agreed that all plants must have 

 had a marine origin also, the case for the sea 

 being the original home of living organisms may 

 be said to be completed. 



It is difficult to picture to ourselves the condi- 

 tion of the earth in those very distant times, 

 when the dry land bore no forests nor grass, the 

 air supported no Birds nor Butterflies, and in the 

 rivers and lakes swam no Fish nor Frogs. It 

 must have been " dry " land indeed, when there 

 were no trees to attract the rain clouds and no 

 herbs or mosses to retain the moisture on the 

 ground. The rivers must have risen and fallen 

 with great rapidity as they carried away the 

 rain that fell in cloud-bursts on the mountain 

 tops. 



But speculation on the character of the land in 

 those times is not within the scope of this work, 



