INVERTEBEATB ANIMALS. 79 



Family MAIADiE. 



Group 190. — Genus MAIA (Lamarck) and allies. 



Estimated number of species, 40; British, 1. 



IT Maia squinado, the Thorn-back-crab, is not un- 

 common on the British coasts and in the 

 Mediterranean. It was well known by the 

 ancients, and was regarded by them as au 

 emblem of wisdom. 



Group 191.— Genus MITHRAX (Leach) and allies. 



Estimated number of species, 40 ; British, 4. 



Groups 190 and 191 constitute the family Maiad^ ; 

 most of the species in 191 have eyes on moveable 

 foot-stalks, capable of being folded back and 

 hidden in the channel of the orbit. 



II Examples of Pisa, Hyas, dc. 



Group 192.— Family INACHID^. Spider-crabs. 

 Estimated number of species, 40 ; British, 6. 



U Leptopodia sagittaria is remarkable for the 

 extreme length and slenderness of its rostrum 

 and limbs. Such a form could exist only in a 

 medium of nearly its own specific gravity. A 

 closely allied species is the colossal Macro- 

 cheira Kaempferi of Japan, having by far the 

 greatest span of any Crustacean. (See case 

 over the east door.) Examples of Stenorhyn- 

 cus, Eurypodius, and other genera. 



