The Coming of Vertebrates and Rise of Fishes 



is possible to identify and locate tbe more 

 abundant and wave-worn fragments. This fish 

 was so like its better-known English cousin, 

 Pterichthys, that 

 the picture of 

 the latter may 

 do duty for both. 



The figures Pterichthys, the wingfish. Very much 

 T . , reduced. 



give a better 



idea of the animal than it is possible to con- 

 vey by words, but it may be noted that the 

 jointed arms occupying the place of the side 

 fins of a fish are really something like the legs 

 of a crab, for they have the hard parts on the 

 outside and the muscles on the inside. This 

 is such a departure from the structure of or- 

 dinary back-boned animals, in which the mus- 

 cles surround the bones, that some naturalists 

 have thought it more than a mere resemblance, 

 and that it hinted at some real relationship 

 between crab and w^ingfish ; w^hile some have 

 even gone so far as to consider this strong- 

 evidence in support of the theory that verte- 

 brates are the descendants of crustaceans. 



95 



