O&USTACEA OP THE MERGUI AECHIPELAGO. 14^ 



arm is also tuberculiferous, and armed at its distal end with a 

 short acute spine (as in M. messor). The outer surface of the 

 wrist is transversely rugose and covered with some small, more 

 or less acute tubercles, also at the internal angle. The hands 

 (PL X. fig. 2) are a little more elongate (less high) than those 

 of M. messor, and differ at first sight by their outer surface 

 being never smooth. The proximal half of the outer surface 

 is covered with many short, oblique, elevated lines, which 

 gradually change towards the fingers into minute granules. As 

 in M. messor, an elevated line, nearly parallel to the rounded 

 and rugose under margin of the hand, proceeds towards the base 

 of the immobile finger. The rounded upper margin is covered 

 with numerous small acute tubercles, and the convex inner sur- 

 face of the hand is granular. The fingers have slightly excavated 

 horny tips, and their somewhat punctate external surface is 

 smooth, but slightly granular at the base ; the thumb appears 

 to be somewhat more slender than that of M. messor, and 

 its upper surface also is covered with small acute tubercles, which, 

 however, are more numerous and somewhat larger than in that 

 species. The under surface of the index is also somewhat 

 tubercular. 



The ambulatory legs present a striking resemblance to those 

 of M.pictus, figured in the ' E"ouvelles Archives.' In M. messor, 

 on the contrary, the penultimate joints (or propodites) are com- 

 paratively much less elongate. 



M. latifrons, White, is probably identical with M. maculatus, 

 and in that case has the priority. 



Dimensions : — 



millim. millim. 

 Distance between the external orbital angles. 29 27 

 Length of the carapace (the front included) . 22^ 21| 

 Breadth of the front (measured between the 



eye-peduncles) 19| 18| 



Length of the propodites of the third pair of 

 ambulatory legs, measured in the middle of 

 the joint , 13| 13 



Metopograpsus maculatus has hitherto been recorded from 

 Batavia {Milne-Edwards) ; and specimens of this species in the 

 Leyden Museum were collected on the coast of Java. 



10* 



