MONTACtUA rOLLEXTANA. 65 



shorter than the superior, with the peduncle extending 

 as far as the middle of the flagellum of the suj)erior. 

 The last joint of the peduncle of the inferior pair is 

 rather longer than the preceding, and the flagellum is 

 rather shorter than the last joint of the peduncle. The 

 first pair of legs are slender, the fourth joint of which is 

 but slightly produced anteriorly below, where it is tipped 

 with long hairs ; the wrist is very long, and fringed upon 

 the lower side with fine hairs ; the hand is much shorter, 

 scarcely more than half the length of the wrist, it is 

 also narrower ; it increases in width towards the palm, 

 which is short and imperfectly defined. The finger is as 

 long again as the palm, and nearly straight. The second 

 pair of legs are longer and stronger than the first ; the 

 hand is twice as long as broad, the upper and lower 

 margins are imperfectly parallel, the form of the organ 

 is therefore oblong-quadrate ; the palm is advanced, 

 smooth, and fringed with a few solitary hairs ; just 

 within the inferior angle is a narrow deep cleft or 

 notch, extending in depth to about one-third the length 

 of the hand, giving to the inferior angle of the palm, 

 which is slightly produced in advance, the appearance 

 of a strong thumb, hollowed upon its internal surface. 

 From this peculiar character the specific name of the 

 animal is derived. The finger is scarcely as long as the 

 palm, and impinges throughout its entire length against 

 that part of the joint. The other legs do not appear to 

 differ much from those of M. monoculoides, except in the 

 unimportant circumstance that the posterior margin of 

 the second joints of the two posterior pairs of legs are 

 not crenulated, and the spines that arm the distal ex- 

 tremity of the feet are crenulated upon one side, and 

 curved at the tip into an imperfect hook, with a small 

 subapical process in the opposite direction, the apices 



F 



