THE PLACOID BRAIN. 149 



ordinary number of from sixty to eighty bones, — a mark — 

 ^he author of the " Yestiges" himself being judge in the case 

 — ^rather of inferiority than the reverse, " Elevation is 

 Biarked in the scale," we find him saying, " by an animal 

 exchanging a multiplicity of parts serving one end, for a 

 smaller number." The skull of a cod consists of about thrice 

 as many separate bones as that of a man. But I do not well 

 see that in this case the fact either of simplicity in excess or 

 of multiplicity in excess can be insisted upon in either direc- 

 tion, as a proper basis for argument. Nearly the same re- 

 mark applies to the maxillaries as to the skulL The under 

 jaw in man consists of a single bone ; that of the thomback 

 — if we do not include the two suspending rihs^ which belong 

 equally to the upper jaw — of two bones (the number in well- 

 nigh Jl the mammiferous quadrupeds); that of the cod, of four 

 bones, and, if we include the suspending rihs^ of twelve. On 

 what principle are we to hold, with one as the representative 

 number of the highest type of jaw, that two indicates a lower 

 standing than /oitr, or four than twelve ? [In reference to the 

 further statement, that in many of the ancient fishes " traces 

 can be observed of the muscles having been attached to the 

 external plates, strikingly indicating their low grade as ver- 

 tebrate animals," it may be answer enough to state, that the 

 peculiarity in question was not a characteristic of the most 

 ancient fishes, — the placoids of the Silurian system, — but of 

 some ganoids of the succeeding systems. The reader may re- 

 member, as a case in point, the example furnished by the nail- 

 like bone of Asterolepis, figured in page 87, in which there 

 exists depressions resembling that of the round ligament in 

 the head of the quadrupedal thigh-bone.] And as for the re- 

 mark that the opening of the mouth of the placoid, " on the 

 under side of the head," is indicative of a low embryonic con 

 dition, it might be almost sufficient to remark, in turn, thai 

 the lowest family of fishes, — that to which the supposed worms 



