Animals Before Man 



fully combining the results obtained from very 

 many sections it was possible to build up 

 these appendages and reconstruct their form. 

 And, after all this had been done, two good- 

 sized specimens came to light with all of the 

 legs in place; and finally 

 a locality was found near 

 liome, N. Y., where many 

 specimens of a small species 

 of trilobite occurred in such 

 an exceptional state of pres- 

 ervation that not only legs, 

 but delicate antennae were 

 clearly to be seen. The 

 long-sough t-f or appendages 

 served, according to their 

 location, as jaws, legs, and 

 breathing organs, being fine 

 examples of the modifica- 

 tion of similar parts for very different purposes. 

 Thus, trilobites are good illustrations of what is 

 termed generalized structure — the absence of 

 special organs, each, or each series, of which is 

 specially devoted to the performance of some 



m 



trilobite, Triarthrus 

 becki, showing the 

 antennae and limbs. 

 About natural size. 

 (After Beecher.) 



