CETJSTACEA OP THE MEEaTJI ARCHIPELAGO. 145 



The upper surface of the thumb, which in these specimens appears 

 a little more arcuate than in the figure 2 e of Hilgendorf, is 

 minutely tubercular, especially near the inner surface, nearly to 

 the tip. The inner surface of the palm presents on its proximal 

 half some rugose lines, which are parallel to the posterior margin, 

 and the inner surface of the index is a little granular at the 

 base. 



Metopograpsus messor has been found in the Eed Sea, through- 

 out the whole Indian Ocean (Zanzibar, Persian Gulf, Nossy-!Faly, 

 coast of Malabar, Mauritius), in the Malayan Archipelago, and 

 extending from Australia to the Piji Islands, New Caledonia, and 

 the Sandwich Islands. 



82. Metopograpsus maculatus, H. M.-Edw. (PI. X. figs. 1-3.) 



Metopograpsus maculatus, H. Milne-Edwards, Ann, Sci. Nat. 3* serie, 

 t. XX. p. 165. 



!Pour specimens were collected in the Mergui Archipelago, one 

 male and three females. 



This species is still very imperfectly known, for so far as I 

 am aware no other description has been published since its first 

 diagnosis, given by the late H. Milne-Edwards. Prof. A. Milne- 

 Edwards, to whom I had sent the male individual of this collec- 

 tioD, informed me that it was M. maculatus, M.-Edw., as I had 

 inferred. I will therefore point out some characters of this 

 Metopograpsus and compare it with M. messor, Eorskal, and 

 M. pictus, A. M.-Edw., the latter of which occurs in the seas 

 of the Moluccas and on the shores of New Caledonia. 



With respect to the general shape of the cephalothorax, 

 M. maculatus appears quite intermediate between the two above 

 mentioned species of this genus, as regards the proportion between 

 the length and the breadth of the carapace. The cephalothorax 

 of-M". maculatus i& somewhat less enlarged and somewhat more 

 elongate than that of 3£. messor ; in the male specimen from 

 Mergui being even more slightly enlarged anteriorly than in 

 the typical specimens from Java, described by the late H. Milne- 

 Edwards. As Prof. A. Milne-Edwards informs me, the pro- 

 portion of the distance between the external orbital angles to 

 the length of the carapace is as 30 : 23 (in M. messor as 30 : 22). 

 The carapace of M. pictus is much more elongate than that of 

 M. maculatus. 



As I have already observed, the front is a little more enlarged 



LINF. JOTJEN. — zoology, YOL. XXII. 10 



