40 MAIAD,*. 



somewhat diverging, so as to leave a triangular space be- 

 tween them. The orbit has a strong spine above its outer 

 angle, and a smaller one at the base of the former ; its 

 superior boundary is arched and rounded. The lateral 

 margin has five or six very strong sharp spines, the an- 

 terior of which bounds the outer angle of the orbit. The 

 upper surface of the carapace is covered with innumerable 

 spines and tubercles. The under surface of the anterior 

 portion is furnished with five strong spines, two on each 

 side on the basal joint of the external antenna, the outer 

 one directed forwards and outwards, the other curved 

 downwards, and a single one at the root of the rostrum, 

 likewise curved downwards. The second and third joints 

 of the antennae of nearly equal length, and inserted at the 

 outer angle of the basal joint. Anterior pair of legs in the 

 adult male nearly twice as long as the carapace, much larger 

 than the succeeding ones ; the arm and wrist tuberculated ; 

 the hand scabrous ; the fingers very taper, pointed, the 

 moveable one slightly curved, scarcely denticulated. The 

 remaining legs cylindrical, without spines or tubercles ; the 

 second pair nearly half as long again as the carapace, the 

 rest diminishing regularly to the fifth ; the last joint very 

 slightly curved, its extremity naked, abruptly smaller, and 

 pointed. The abdomen is in each sex seven-jointed. In 

 the male, the second joint is very narrow at the insertion 

 of the last pair of legs, the anterior part of it becoming 

 abruptly much wider ; the sides of the remainder are 

 nearly parallel, becoming, however, a little narrower, and 

 the tei-minal margin is rounded. It has a broad carina 

 occupying one- third of its breadth. In the female it is 

 oval. 



There are few species of Crustacea in the torm of which 

 age produces so great a change as in this. The younger in- 



