CRUSTACEA OF THE MEEGTJI ARCHIPELAGO. 177 



margin ; this character is presented also by S. hidens and S. gut- 

 tata, but never by S. Dussumieri. In both species the inner 

 surface of the hands is only faintly granular. The joints of the 

 male abdomen are quite similar in S. HaswelU and S. bidens ; the 

 figure of the latter in the ' Fauna Japonica ' may therefore be 

 consulted. 



Dimensions of the larger specimen : — 



millim. 



Distance between the extraorbital teeth 17-|- 



Length of the cephalothorax , 13| 



Sesarma HaswelU occurs also at Ceylon, and I have little 

 doubt that the specimen recorded by Hilgendorf from that 

 locality belongs to S. HaswelU (Crustaceen von Ost-Africa, 

 p. 91, in V. d. Decken's Eeisen). 



I now add for comparison the distinctive characters of S. 

 guttata, which inhabits the eastern coast of Africa. This species 

 is also most closely allied to S. bide?ts, but the tubercles of the 

 upper margin of the mobile finger are larger and more prominent, 

 and the penultimate joint of the male abdomen is comparatively 

 much longer, the proportion of the breadth of its posterior margin 

 to the length being in S. guttata as 7 : 5, and in S. hidens as 7 : 3|. 

 The prominent tooth near the distal end of the anterior margin 

 of the arm, which in ;S^. bidens is very acute, simple, and spinif orm, 

 is represented in >S^. guttata by an acute dentiform prominence, 

 which is itself a little denticulate. The second antero-lateral 

 teeth of the cephalothorax are somewhat more prominent in S. 

 guttata. In other respects these two forms closely resemble 

 one another. 



97. Sesarma Dussumieri, M.-Edw. (PL XII. figs. 8-12.) 



Sesarma Dussumieri, Milne-JEdwards, Annales des Sciences Naturelles, 

 t. XX. 1853, p. 185. 



One fine male specimen was collected at Tavoy. 



Sesarma Dussumieri was unsatisfactorily characterized by the 

 late H. Milne-Edwards, and it has therefore never been recog- 

 nized by subsequent authors. It differs more from 8. bidens 

 than from Sesarma HaswelU and S. guttata. Except in the 

 abdomen of the male, the joints of which have a different 

 form, the cephalothorax of Sesarma Dussumieri resembles that 

 of Sesarma bidens. The third joint of the male abdomen, 

 which is the broadest of all, is comparatirely shorter in S. Bussu-^ 



LIKJS. JOUEIir. — ZOOLOGY, VOL, XXII. 12 



