INVERTEBKATE ANIMALS. 81 



Group 189. -Family PARTHENOPID^. The species all 

 live amongst rocks in moderately deep water; they move 

 slowly, and notwithstanding their grotesquely rugged 

 aspect, cannot be formidable except to animals much 

 inferior in size to themselves. The single British 

 species, the Strawberry- crab, is said to use its long 

 arms in climbing. 

 Estimated number of species, 20 ; British, 1 . 



U Examples of Parthenope, Lambrus, and Crypto- 

 poda, &c. 



Family MAIAD^. 

 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 an 

 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 movable 

 foot-stalks, capable of being folded back and 

 hidden in the channel of the orbit. 

 U Examples of Pisa, Tlyas, &c. 



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

 Estimated number of species : 40 ; British, 6. 



IT Leptopodia sagittaria is remarkable for the 

 extreme length and slenderness of its rostrum 

 and limbs. Such a form could exist onlv in a 



