THE HORSESHOE CRAB. 





Class II. — Podostomata {King-crab, Eurypterus, 



Trilobites). 



Order 1. Merostomata. — The only living represents*! 



of this order is the horsesh ■ king-crab ( /. 



phemus, Fig. 1 "."-')., which ranges from Casco Bay, Maine, 

 tn Florida and the Wesi [ndii 



J'ho body of the king-crab is v< xy lai irly two 



. 



- ' - • ■ 1 



¥* 



kg. 119.— Common Shore-crab (Cancer tm I Natural size Froi 



fni in length; it consists of :i head composed of six segn 

 an abdomen with nine segments, the ninth ming a 



spine. The head is broader than long, in sbapi dial like that 



of Apu8, with a broad flal triangular fold on the urn 

 are two large lunate compound eyes, mar the middle i>f the 1 

 but quite remote from each other, and two small compound 

 uated close together near the fronl i dge of the head. There are no 

 antenna', and the six pairs of a] n of uniform shape like 



m»t like mandibles <>r maxillae, and are adapted fur walking; 

 the feet are provided with sharp teeth on the basal joint for retain- 



