I. '21. 20 



edge, and reaches the middle of the fourth joint. The 

 acicle bears a sharp tooth at the inner side of the base ; it is 

 slightly curved and does not reach the middle of the fifth joint. 

 The third and fourth joints are of the usual form. The fifth 

 is much longer than any of the others, and is laterally com- 

 pressed. The whole peduncle bears setae in greater or less pro- 

 fusion, but they are most plentiful on the inner side of the 

 second joint and on the acicle. Each joint of the fiagellum 

 bears two or three long slender hairs. 



The form of the right cheliped, which is as usual much larger 

 than the left, is very characteristic. There are two or three 

 irregular rows of small teeth on the upper surface of the car- 

 pus, and a row of about ten much larger, strong, curved teeth 

 on the upper inner margin of the same joint. There are also 

 two or three teeth on the upper distal margin, pointing towards 

 tlie propodite. The carpus has a sparse covering of fine silky 

 hairs which are most numerous on the inner edge and near 

 the distal end. 



The inner margin of the hand, from the base of the 

 propodite to the tip of the dactyl is almost straight. The 

 dactyl curves only very slightly towards the fixed finger near 

 the tip. The outer margin, on the other hand, is more or less 

 crescent-shaped. Along its entire length there is a row of strong 

 distinct teeth, which reach their greatest development about 

 the middle of the fixed finger. They are all slightly upturned 

 and decrease in size towards the proximal end of the joint 

 until they become hard to distinguish from mere tubercles. 

 There is a row of similar, but rather smaller teeth, on the inner 

 margin of the propodite. This row is continued on the edge 

 of the dactyl. The fingers taper to narrow points which end 

 in blunt yellow claws, their tips crossing slightly when closed, 

 the dactyl tip passing below that of the fixed linger. 



The name of this species refers to the deeply sculptured 

 upper surface of the right chela. It bears three deep de- 

 pressions. The first of these is confined to the proximal half of 

 the propodite and lies towards the inner edge ; it is slightly 

 narrower distally than behind and has sharply defined margins. 

 The second depression lies on the outer half of the propodite, 

 separated in its proximal part from the first depression by 

 a well-marked but blunt ridge. It is narrow at its proximal 

 end, widens in the middle, the widest point being just op- 

 posite the base of the dactyl, and fades away gradually towards 

 the tip of the fixed finger. Its margin is steep on the inner 

 part of the proximal half, but forms a more or less gentle slope 

 elsewhere. The axis of the third depression lies along the line 

 of contact of the fixed finger with the dactyl. Each finger 

 has a slight rounded median ridge and from this the surface 

 slopes rapidly downwards so as to form a marked hollow be- 

 tween the fingers. Besides the ridge already mentioned 

 between the hrst and second depressions there is another 

 between the first depression and the inner edge of the 



