THE VERTEBRATA 143 



Let us now consider some other creatures 

 that resemble vertebrates in some ways, and 

 help to form the group of Chordata. Balano- 

 glossus is one of them, the Acorn-tongue Ani-mal. 

 This odd name is given to it on account of a 



FlG. 42. Scales of the Common Sole, highly magnified. 



structure which is called (like the elephant's 

 trunk) a Proboscis ; this may be compared with 

 a tongue, so far as its use goes, for it is thrust 

 out to catch prey and again drawn in. It is oval 

 in shape, and therefore fancifully compared to an 

 acorn. It is highly sensitive, being richly sup- 

 plied with nerves. The creature is to all intents 

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