REPORT ON THE BRACHYURA. 
59 
end of the merus-joints in all the legs, this being represented in Hyastenus oryx by a 
small blunt tooth. 
Adult $ . 
Lines. 
Millims. 
Length of carapace to base of rostrum, nearly 
• H 
17-5 
Length of rostrum, ..... 
.71 
15-5 
Greatest breadth of carapace, nearly 
51 
11 
Length of ambulatory leg of first pair, . 
. 21 
44 
The unique female specimen in the collection was dredged near the Ki Islands in 
140 fathoms, lat. 5° 49' 15" S., long. 132° 14' 15" E. (Station 192), and although of 
comparatively large size, is apparently not fully adult. 
As this form in so many of its characters resembles Hyastenus oryx, I have not 
thought it necessary to do more than indicate the points in which it differs from that 
species, of which it is possible that a sufficient series would show it to be merely 
a well-marked deep-water variety ; I cannot, however, venture to unite it with 
Hyastenus oryx on the authority of the series at present existing in the British 
Museum collections. 
Naxia, Milne Edwards. 
Naxia, Milne Edwards, Hist. Nat. Crust., vol. i. p. 313, 1834. 
,, Miers, Journ. Linn. Soc. Lond. (Zool.), vol. xiv. p. 658, 1879, et synonyma. 
Carapace subpyriform, moderately convex, rounded behind, and armed with spines or 
tubercles on the dorsal surface. A prseocular spine usually present, and when present 
well developed. Spines of the rostrum well developed, subcylindrical, parallel or 
divergent, and bearing on the inner margin, near to the extremities, a small accessory 
spine or spinule. Post-abdomen (in the male) distinctly seven-jointed (in the female 
some of the segments may be coalescent). Eyes small, retractile within the small orbits, 
which may have a single or a double hiatus in the superior margin, and a wider hiatus in 
the inferior margin. Antennae with the basal joint enlarged, with a spine or tubercle at 
the antero-lateral angle, and sometimes with another on the exterior margin ; the 
flagellum exposed, or partially concealed in a dorsal view by the rostral spines. Merus 
of the exterior maxillipedes distally truncated, with the antero-external angle little, if at 
all, produced, and the antero-internal angle emarginate. Chelipedes (in the male) slender 
and moderately developed, palm usually somewhat elongated, fingers denticulated near 
the distal extremity, and having between them when closed a small hiatus at the base. 
Ambulatory legs slender and somewhat elongated, the first pair much the longest, with 
the joints subcylindrical ; dactyli nearly straight. 
The following are, I believe, the only recorded species of this genus, which can only 
be distinguished from Hyastenus and Pisa by the accessory spinules of the rostrum : — 
