252 
THE VOYAGE OF H.M.S. CHALLENGER. 
Euplax ( Chxnostoma) boscii (Audouin). 
Macrophtlialmus boscii, Audouin, Explic. des planches in Savigny, Crust, de l’Egypte, pL ii. fig. 1. 
Euplax boscii, Milne Edwards, Ann. d. Sci. Nat., ser. 3, Zool., vol. xviii. p. 160, 1852. 
„ ( Chxnostoma ) boscii, A. Milne Edwards, Nouv. Archiv. Mus. Hist. Nat., vol. ix. p. 281, 
1873, and reference to synonyma. 
„ „ ,, Miers, Crust, in Rep. Zool. Coll. H.M.S. “Alert,” pp. 238, 542, 
1884. 
Fiji Islands, Kandavu, July 1874 (an adult female, bearing ova). 
Adult $ . Lines. Millims. 
Length of carapace, nearly . . . . . . 5 10 ‘5 
Breadth of carapace, nearly . . . . . . 6 12-5 
Family III. Grapsid^e. 
Ghrapsoidiens, Milne Edwards, Hist. Nat. Crust, vol. ii. p. 68, 1837. 
Grapside e, Dana, U.S. Explor. Exped., vol. xiii., Crust., p. 329, 1852. 
„ Kingsley, Proc. Acad. Nat. Sci. Philad., p. 187, 1880. 
Grapsinx (pt.), Milne Edwards, Ann. d. Sci. Nat., ser. 3, Zool. xx. p. 163, 1853. 
Carapace depressed or moderately convex, more or less quadrilateral, with the lateral 
margins straight or slightly arcuated. Front usually broad, more rarely of moderate 
width, never very narrow. Orbits and eye-peduncles of moderate size. The post-abdomen 
usually covers the whole width of the sternum at the base, between the coxae of the fifth 
ambulatory legs. The carpal joint of the endognath of the exterior maxillipedes articu- 
lates at the summit or at the antero- external angle of the merus, not at the antero-internal 
angle. The chelipedes (in the adult males) are usually subequal and are moderately 
developed. The dactyli of the ambulatory legs are styliform, compressed, and are some- 
times smooth, sometimes armed with strong spines. 
The species are nearly always littoral or shallow-water forms, but rarely inhabit deep 
water (e.g., Euchirogrcipsus). Both genera and species have been recently enumerated 
by Kingsley in the memoir cited above. 
Subfamily 1 . Grapsiile. 
Grapsinx, Kingsley, tom. cit., p. 189. 
Antennules more or less transverse and covered by the front, which is entire, not 
longitudinally cleft. 
This subfamily is divided by Mr. Kingsley (after Dana) into the following sections 
(or tribes) : — 
