METOPOGRAPSUS MESSOR. 183 



two on the inner margin and two an the outer margin, 

 one being placed near the articulation of the hand and 

 the other between the two spines of the inner margin; 

 the upper surface of the hands is somewhat hairy between 

 these spines ; the convex outer , lower and inner surfaces 

 are quite smooth , besides a smooth , scarcely visible crest 

 on the middle of the external surface and an equally smooth 

 crest near the lower margin , that proceeds upon the index. 

 The fingers are grooved and toothed on their inner margins. 

 The male abdomen is formed by 5 joints. The meropodites 

 of the posterior ambulatory legs are slightly grooved, with 

 a sharp spine on the distal end of the lower margin and 

 the lower margin of the penultimate joint is toothed. 



Breadth of carapace of the largest specimen 33 mm , 

 length 21 mm. 



Though closely allied to Thai, arcuata de Haan = sima 

 M. Edw., our species may be distinguished at first sight 

 by its quite smooth., never granular, very convex hands. 



17. Neptunus pelagicus L. 

 Heller, 1. c. pag. 355. 



A great number of young specimens are in the collection , 

 which are all ornamented with the dark red spot on the 

 inner surface of the hand before the articulation of the 

 mobile finger , as described by Heller. 



18. Metopograpsus messor Forsk. 

 Milne Edwards, Ann. Scienc. Nat. 1853, pag. 165. 



A single specimen is in the collection. Which may be 

 the difference between Metopogr. messor Forsk. and Grapsus 

 [Pachygrapsus] aethiopicus Hilgendorf (Baron v. d. Decken's 

 Reise, pag. 88, tab. 4 fig. 2). Our specimen at least, 

 though entirely agreeing with the figure , positively belongs 

 to Metopogr. messor , observed by Forskal and described also 

 by Heller as found in the Red Sea (and not in fresh water). 



Notes irom the Leydcn Museum, Vol. II. 



