THE PLACOID BRAIN 135 





THE PLACOID BRAIN. 



EMBRYONIC CHARACTERISTICS NOT NECESSARILY OB 

 A LOW ORDER. 



That special substance according to whose mass and degree 

 of development all the creatures of this world take rank in 

 the scale of creation, is not boney but brain. Were animals 

 to be ranged according to the solidity of their bones, the class 

 of birds would be assigned the first place ; the family of the 

 FelidcB, including the tiger and lion, the second ; and the 

 other terrestrial carnivora the third. Man and the herbivo- 

 rous animals, though tolerably low in the scale, would be in 

 advance of at least the reptiles. Most of these, however, 

 ^fr-ould take precedence of the sagacious Delphinidce; the osse- 

 ous fishes would come next in order ; the true placoids would 

 follow, succeeded by the Sturiones ; and the Suctorii, i. e. 

 Cyclostorni or lampreys, would bring up the rear. There would 

 be evidently no order here : the utter confusion of such an 

 arrangement, like that of the bits of a dissected map flung 

 carelessly out of its box by a child, would of itself demon- 

 strate the inadequacy and erroneousness of the regulating 

 principle. But how very different the appearance presented, 

 when for solidity of bone we substitute development of brain! 

 Man takes his proper place at the head of creation ; the lower 



