20 4 
THE VOYAGE OF H.M.S. CHALLENGER. 
An adult and two immature males, and two adult females, were dredged near the Ki 
Islands, in 140 fathoms, lat. 5° 49' 15" S., long. 132° 14' 15" E. (Station 192). 
In the adult female the post-abdomen is rather narrow, broadest at the sixth joint. 
In the small males the carapace is more convex and uneven, the eyes very large, the 
marginal spines of the carapace are relatively longer, and the penultimate and terminal 
joints of the fifth legs are fringed with longer hairs. One of these has the following 
dimensions : — 
Young <?. 
Lines. 
Millims. 
Length of carapace and rostrum, 
13-5 
Breadth of carapace, .... 
7i 
15-5 
Length of a chelipede, .... 
11 
23-5 
Length of fifth leg, ..... 
18 
This very remarkable Platyonychus is allied to the East American Platyonychus 
ocellatus in the form of the frontal spines, and to the Oriental Platyonychus bipustulatus 
in the structure of the merus of the outer maxillipedes, but differs from both in the 
strongly -granulated and spinuliferous palm and dactyl of the chelipedes, the more slender 
dactyli of the ambulatory legs, the iridescent reflections of the limbs, &c. 
Lissocarcinus, Adams and White. 
Lissocarcinus, Adams and White, Crust, in Zool. H.M.S. “Samarang,” p. 45, 1848. 
„ A. Milne Edwards, Archiv. Mus. Hist. Nat., vol. x. p. 417, 1861. 
Carapace depressed, smooth, transverse, little, if at all, broader than long, with the 
frontal margins and the antero-lateral margins of the carapace thin, acute, the lateral 
margins either subentire or divided into five lobes or teeth. The front projects some- 
what beyond the level of the orbits, and is either subentire or divided by a median 
notch into two lobes, which may be separated on each side by a slight incision from the 
interior angle of the orbit. The ridges of the endostome are usually developed, but 
indistinct. The post-abdomen of the male in Lissocarcinus orbicularis 1 is five-jointed, 
with the third to the fifth segments coalescent. The eyes are very short. The basal 
antennal joint is dilated, but not transverse, occupies the interior hiatus of the 
orbit, and is slightly produced at its antero-external angle. The ischium of the 
endognath of the exterior maxillipedes is not produced at its antero-internal angle, the 
merus is longer than broad, obliquely truncated along the interior margin, and is not 
greatly produced at its antero-external angle. The chelipedes are short, subequal ; merus 
trigonous, carpus with a spine on its interior margin, palm short, either smooth or 
costated externally, fingers strongly dentated on the inner margins, the dactylus some- 
times carinated above. Ambulatory legs very short, with the dactyli styliform ; fifth or 
1 This is the only species of which I have examined males. 
