28 



THE GEOLOGICAL HISTORY OF PLANTS. 



Owen, and which were by him referred to crustaceans 

 probably resembling Limulus, were shown by the writer, 

 _ in 1862,* to correspond 



nary feet, and the central furrow by the tail. It was also 

 shown that when the Limulus uses its swimming-feet it 

 produces impressions of the character of those named 



Fig. 6. — Trail of Carboniferous crustacean (RusicJinites Acadicus), Nova 

 Scotia, to illustrate supposed Algae. 



precisely with those of the 

 American Limulus {Poly- 

 phemus Occident alis) (Fig. 

 5). I proved by experi- 

 ment with the modern ani- 

 mal that the recurring se- 

 ries of groups of markings 

 were produced by the toes 

 of the large posterior tho- 

 racic feet, the irregular 

 scratches seen in Protich- 

 nites lineatus by the ordi- 



Fig. 5. — Trail of a modern king- 

 crab, to illustrate imitations of 

 plants sometimes named Bilo- 

 bites. 



* " Canadian Naturalist," voL vii. 



