NATURAL HISTORY OF CREATION. 151 



ovum, resemble the perfect animal of the inferior order 

 entomostraea, and pass through all the forms of transi- 

 tion which characterise the intermediate tribes of Crus- 

 tacea. The salmon, a highly organised lish, exhibits, in 

 its early stages, as has been remarked, the gelatinous 

 dorsal cord, the heterocercal tail, and inferior position of 

 tlie moutli, which mai'k the mature example of the lower 

 tribes of lishes, the placoids and ganoids. The frog, 

 again, for some time after its l)irth, is a fish with ex- 

 ternal gills, and other organs fitting it for an aquatic life, 

 all of which are changed as it advances to maturity, and 

 becomes a land animal. The mammifer only passes 

 through still more stages, according to its higher place in 

 the scale. Nor is man himself exempt from this law. 

 His first form is that which is permanent in the animal- 

 cule. - His organisation gradually passes through con- 

 ditions generally resembling a fish, a reptile, a bird, and 

 the lower mammalia, before it attains its specific maturity. 

 At one of the last stages of his foetal career, he exhibits 

 an intermaxillary bone, which is characteristic of the 

 pei'feet ape ; this is suppressed, and he may then be said 

 to take leave of the simial type, and become a true human 

 creature. Even, as we shall see, the varieties of his race 

 are represented in the progressive development of an 

 individual of the highest, before vve see the adult 

 Caucasian, the highest point yet attained in the animal 

 scale. 



To come to particular points of the organisation. 

 The brain of man, which exceeds that of all other 

 .animals in complexity of organisation and fulness of 

 development, is, at one early period, only '* a simple fold 

 of nervous matter, with difficulty distinguishable into 

 three parts, while a little tail -like prolongatioii towards 

 the hinder parts, and which had l)een the first to appear, 



