94 THE STORY OP THE EARTH AND MAN. 



Society's Memoirs, it must have been six feet in 

 length, and nearly two feet in breadth. Its antennae 

 were, unlike the harmless feelers of modern Crustacea, 

 armed with powerful claws. Two great eyes stood 

 in the front of the head, and two smaller ones on 

 the top. It had four pairs of great serrated jaws, 

 the largest as wide as a man's hand. At the sides 

 were a pair of powerful paddles, capable of urging 

 it swiftly through the water as it pursued its prey ; 

 and when attacked by any predaceous fish, it could 

 strike the water with its broad tail, terminated by a 

 great flat " telson," and retreat backward with the 

 rapidity of an arrow. Woodward says it must have 

 been the ' ' shark of the Devonian seas ; " rather, it was 

 the great champion of the more ancient family of the 

 lobsters, set to arrest, if possible, the encroachments 

 of the coming sharks. 



The Trilobites and Eurypterids constitute a hard 

 case for the derivationists. Unlike those Melchi- 

 sedeks, the fishes of the Silurian, which are without 

 father or mother, the Devonian crustaceans may boast 

 of their descent, but they have no descendants. No 

 distinct link connects them with any modern crusta- 

 ceans except the Limuli, or horse-shoe crabs; and here 

 the connection is most puzzling, for while there 

 seems some intelligible resemblance between the adult 

 Eurypterids and the horse-shoe, or king-crabs, the 

 latter, in their younger state, rather resemble Trilo- 

 bites, as Dr. Packard has recently shown. Thus 

 the two great tribes of Eurypterids and Trilobites 



