236 
THE VOYAGE OF H.M.S. CHALLENGER. 
The single species, Notonyx nitidus, which has been referred to this genus, occurs, but 
rarely, at New Caledonia and the Fiji Islands, and has been taken by the Challenger off 
the south coast of New Guinea in 28 fathoms. 
Notonyx is very nearly allied to Ceratojplax, and were it not for a slight difference in 
the form of the merus of the exterior maxillipedes, could, I think, hardly be distinguished 
from that genus. 
Notonyx nitidus , A. Milne Edwards. 
Notonyx nitidus, A. Milne Edwards, Nouv. Arehiv. Mus. Hist. Nat., vol. ix. p. 269, pL xii. 
fig. 3, 1873. 
South of New Guinea, 28 fathoms, in lat. 9° 59' S., long. 139° 42' E. (Station 188). 
An adult but small male and an adult female. 
Adult $ . Lines. Millims. 
Length of carapace, rather over ...... 3 7 
Breadth of carapace, rather over ...... 4 9 
In these specimens, the slender basal antennal joint does not quite reach the subfrontal 
process ; the merus of the exterior maxillipedes, as in the description of Milne Edwards, 
is not produced at the antero-external angle, and herein differs from the figure cited, 
where it is shown as slightly produced. 
Subfamily 2. Ocypodina:. 
Ocypodiens, Milne Edwards, Hist. Nat. Crust, vol. ii. p. 39, 1837. 
Gonoplaciens (pt.), Milne Edwards, tom. cit., p. 56, 1837. 
Carapace transverse, trapezoidal or quadrate, with the antero-lateral angles frequently 
produced and acute, and the lateral margins straight, entire or incised ; front narrow or 
of moderate width. Orbits usually very considerably developed and occupying nearly 
the whole or a great part of the anterior face of the body below the front. The fifth 
joint of the exterior maxillipedes usually articulates at the antero-external angle of the 
merus. Chelipedes in the adult male subequal, or sometimes very unequal. Ambulatory 
legs moderately elongated, with the dactyli styliform, compressed, not spinose. 
I divide the genera of this group into three sections, as follows : — 
1. Ocypodinse. 
Carapace trapezoidal with the antero-lateral margins not greatly produced, and entire ; 
the fifth joint of the endognath of the exterior maxillipedes articulated at its apex, or at 
