Eimer on Growth and Inheritance 423 



drawn from the phenomena presented by the eyes of flat 

 fishes, and this is brought forward by Mr. Cunningham in 

 support of his, and Eimer's, Neo-Lamarckism. The very 

 same argument was, indeed, brought forward by us twenty 

 years ago.^ Flat fishes (that is, such fishes as the sole, 

 flounder, brill, turbot, etc.) when young, have the eyes situated 

 as usual, i.e. one on each side. As they become adult, how- 

 ever, one passes over, so that both eyes come to be upon one 

 side (right or left) of the head. This could not have been 

 brought about by the minute changes of natural selection, 

 since the mere transit of the eye for a small fraction of its 

 ultimate journey could never have been the means of saving 

 a life. This is the more evident since in the young turbot 

 and brill the metamorphosis is very nearly or quite com- 

 pleted long before the Httle fish have retired to the sea- 

 bottom. 



Mr. Cunningham well observes : — ^ 



* Nothing can test better the claims of the two theories — the Neo- 

 Lamarckian and the Neo-Darwinian ^ — to be accepted in explanation 

 of the origin of adaptations than the case of the woodpecker. This 

 bird lives entirely on insects, and only catches insects in one way — a 

 very peculiar way. It probes the holes in the bark of trees made by 

 insects, or makes holes itself, and then inserts its long, pointed tongue, 

 whose tip is provided with recurved papillae, like a narrow bottle- 

 brush, and with this extracts the maggots. The rapid protrusion of 

 the tongue to a considerable distance, and its sudden retraction, are 

 rendered possible by the elongation of the processes of the hyoid bone, 

 to which the tongue is attached. These processes are bent upwards 

 and forwards over the back of the skull, and inserted near the orbits. 

 Now, in all birds the tongue is attached to the hyoid bone, and moved 

 by the muscles connected with it ; in nearly all birds the tongue is 



^ See The, Genesia of Species, p. 41. 



2 Page xvi. 



3 The term ' Neo-Darwinian ' is applied to Professor Weismann and to 

 each of his supporters, in spite of the fact that he to whom they appeal would 

 have repudiated them. The epithet ' Neo-Lamarckian ' is given to those 

 who sympathise with Professor Eimer. 



