EVOLUTION OF THE MIND. 447 



from the facts presented, it is certainly no longer to be 

 doubted that this has actually developed gradually, step by 

 step, from the long ancestral series of Vertebrates ; but it is 

 quite otherwise with the ' spirit of man,' with the human 

 mind, which cannot possibly have developed in a similar 

 way from the mind of lower Vertebrates." Let us see if the 

 known facts of Comparative Anatomy, Physiology, and 

 Evolution can meet this grave objection. We shall best 

 gain firm ground from which to start in this matter by 

 comparatively examining the minds of the different Verte- 

 brates. Side by side within the various classes, orders, 

 genera, and species of Vertebrates, we find so great a variety 

 of vertebral intellects, that, at first sight, one can scarcely 

 deem it possible that they can all be derived from the mind 

 of a common " Primitive Vertebrate." First, there is the 

 little Lancelet, which has no brain at all, but only a simple 

 medullary tube, the entire mental capacity remaining at 

 the very lowest grade occurring among Vertebrates. The 

 Cyclostomi, also, standing just above, exhibit a hardly 

 higher mental life, though they have a brain. Passing on to 

 Fishes, we find their intelligence, as is well known, also 

 at a very low point. Not until from these we ascend to the 

 Amphibia, is any essential progress in mental development 

 observable. This is much greater in Mammals, although, 

 even here, in the Beaked Animals (Ornithostoma), and the 

 next higher class, the stupid Pouched Animals (Marciipials), 

 the entire mental activity is still of a very low order; but 

 if we pass on from these to Placental Animals, within this 

 multiform group we find such numerous and important 

 steps in differentiation and improvement, that the mental 

 differences between the most stupid Placental Animals (for 



