TRANSLATOR'S PREFACE xvii 



in explanation of the origin of adaptations than tlie 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 papillce, 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 tlie 

 elongation of the processes of the hyoid bone to which tlie 

 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 that 

 bone : in nearly all birds the tongue is muscular and mobile. 

 It is admitted even by Weismann's adherents that the size 

 and shape of bones, the size and shape of muscles, are in 

 the individual modified by the use which is made of them 

 It will also probably be admitted that the modification is 

 such as to facilitate the operations in which they are used. 

 Therefore in every generation of woodpeckers — which birds, 

 in the struode for existence, had to be content to pick up 

 a livino- on tree-trunks or starve — the constant use of the 

 tongue in extracting insects from holes in trees must liave 

 elongated the tongue and hyoid bone, and increased tlie 

 power of protrusion of the organ in each individual. TIr' 

 Neo-Lamarckians believe that these individual modifications 

 were inherited in some degree, so that a greater moditicati«ui 

 in the same direction was produced in the oftspring, and m 

 this way it is easy to understand how the degree of special- 

 isation we now see was produced. 



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