20 
THE VOYAGE OF H.M.S. CHALLENGER. 
Inachus leptochirus, Leach. 
Inachus leptochirus, Leach, Malacostraca Podophthalmata Britannise, pi. xxii. B. 
,, „ Bell, British Crust., p. 18, 1853. 
„ ,, Heller, Crust, des siidlichen Europa, p. 32, pi. i. figs. 12, 13, 1863. 
,, leptorinchus, Milne Edwards (after Desmarest), Hist. Nat. Crust., vol. i. p. 289, 1834. 
A small male and two small females were dredged in 50 to 90 fathoms, near Fayal, 
Azores. 
Adult $ . 
Lines. 
Millims. 
Length of carapace, ...... 
H 
7-5 
Breadth of carapace, nearly ... 
6-5 
Length of chelipede, nearly ..... 
9 
Length of first ambulatory leg, .... 
13 
27-5 
Oncinopus, de Haan. 
Oncinopus, de Haan, Crust, in v. Siebold, Fauna Japonica, p. 87, pi. H., 1839. 
,, Miers, Journ. Linn. Soc. Lond. (Zool.), vol. xiv. p. 645, 1879. 
Carapace semi-membranaceous, elongate, narrow-triangulate, and depressed. Rostrum 
very short, composed of two vertically compressed laminiform lobes, no prse- or postocular 
spines. Post-abdomen in both sexes distinctly seven-jointed. Eyes slender and 
projecting laterally. Antennae with the basal joint very short and slender, and not 
attaining the front, the flagella exposed and visible at the sides of the rostrum ; merus of 
the exterior maxillipedes elongated and articulated with the next at its summit. 
Chelipedes in the male rather small, with the palm turgid, and the fingers having 
between them, when closed, an interspace at the base. Ambulatory legs slender and some- 
what elongated, with the penultimate joints of the first and second pairs dilated, com- 
pressed and ciliated on the posterior margin ; the dactyli in all slightly arcuated and 
retractile against the penultimate joints. 
The described species, as. I have already shown, are probably all to be regarded as 
synonymous with Oncinopus aranea, de Haan, the type of the genus, which ranges 
from the seas of Japan through the Malaysian Seas eastward to the New Hebrides, and 
in bathymetrical range, from shallow water, to a depth, as the Challenger collections show, 
of 825 fathoms. 
Oncinopus aranea, de Haan. 
Oncinopus aranea, de Haan, Crust, in v. Siebold, Fauna Japonica, p. 100, pi. xxix. fig. 2, <?, $>, 
and pi. H, 1839. 
„ „ Miers, Crust, in Report on Zoological Collections of H.M.S. “Alert,” p. 190, 
1884, et synonyma. 
Specimens are referred to this species from the following localities : — An adult 
female from a bottle labelled “ April, 74, 2 to 10 fathoms,” and therefore obtained on the 
