1900.] A. Alcock — GarcinoJogical Fauna of India. 397 



grooves are present on the lateral parts of the branchial regions : the 

 antero-lateral, or outer orbital angle, is acnte, but there are no teeth on 

 the lateral border behind it. 



Front very broad, more than half the extreme width of the 

 carapace, deflexed : along the line of flexion are four depressed lobes, the 

 outer one of which on either side sometimes shows a tendency to split 

 into two. 



Orbits of moderate size, occupying the corners of the carapace : 

 the lower border is notched near its outer end : the orbital hiatus is 

 filled by a special lobe which belongs to the inner of the two fossae into 

 which the orbit is divided and this lobe completely excludes the 

 antennae from the orbit. The antennules fold nearly transversely in 

 fossae of good size. The antennae have a short and slender flagellum : 

 the basal joint of the peduncle is not very massive. 



Epistome well defined, but short fore and aft. Buccal cavity 

 square with the anterior corners rounded off. The external maxillipeds 

 leave between them a rhomboidal gap in which the mandibles are 

 exposed : the merus is shorter than the ischium, and carries the coarse 

 palp at or near the antero-external angle. 



Chelipeds either subequal or unequal, the larger one much more 

 massive than the legs but shorter than the 2nd and 3rd pairs of these : 

 fingers rather short and stout, with the tip spooned. 



Legs broad and compressed, especially as to the merus, which 

 joint — like the arm of the chelipeds — usually has some squamiform 

 markings : the last three joints have bristly edges and the dactylus is 

 thorny. 



The abdomen in both sexes consists of 7 separate segments, and 

 in the male its base is as broad as the sternum between the last pair 

 of legs. 



An Indo-Pacific genus. 



86. Metopograpsus messor (Forskal) Edw. 



Cancer messor, Forskal, Descrip. Anim. in itin. orient, p. 88. Grapsus messor, 

 Milne Edwards, Hist. Nat. Crust. IT. 8S : Krauss, Sndafr. Crust, p. 43 : Hoffmann in 

 Pollen & Van Dam, Faun. Madag. Crust, p. 23 : Sluiter, Tijds. Nederl. Ind. XL. 

 1881, p. 164. Metopograpsus messor, Milne Edwards, Ann. Sci. Nat., Zool., (3) XX. 

 1853, p. 165: Heller, SB. Ak. Wien, XLIII. 1861, p. 362, and Novara Crust, p. 44: 

 A Milne Edwards, Nouv. Archiv. da Mus. IV. 1868, p. 71: Kossmann, Reise roth. 

 Meer., Crust, p. 57: Hilgendorf, MB. Ak. Berl. 1878, p. 808: Miers, Phil. Trans. 

 1879, p. 489, and Zool. H. M. S. Alert, pp. 184, 245, 518, 545, and Challenger 

 Brachyura, p. 258: de Man, Notes Leyden Mus. II. 1880, p. 183, and Journ. Linn. 

 Soc. Zool. XXII. 1887-1888, p. 144, pi. ix. fig. 11, and Archiv f. Naturges. LTII. 1888, 

 i. p. 361, pi. xv. fig. 6, and in Weber's Zool. Ergebn. Niederl. Ost. Ind. II. p. 314: 



