228 
THE VOYAGE OF H.M.S. CHALLENGER. 
merus and carpus-joints are granulated, and the carpus has usually two spiniform teeth on 
its inner margin ; the palm (in the larger chelipede) is robust and somewhat turgid, 
granulated near the base, and elsewhere smooth ; the fingers dentated on the inner 
margins and rather shorter than the palm ; in the smaller chelipede both wrist and palm 
are externally covered with numerous, crowded, acute granules, and the fingers are 
relatively longer ; the ambulatory legs are slender, with the superior margins of the 
fourth to the sixth joints granulated ; dactyli styliform, slightly hairy, and terminating 
in a short claw. The male verges are inserted very near the bases of the fifth legs. 
Colour (in spirit) yellowish-brown ; fingers black or brownish. 
Adult $ . Lines. Millims. 
Length of carapace, about . . . . . . 3 6'5 
Breadth of carapace, nearly ...... 4 8 
Off Nightingale Island, Tristan da Cunha Group, October 17, 1873, in 100 fathoms 
(a good series of specimens) ; Agulhas Bank, off Cape Agulhas, South Africa (Station 142), 
in lat. 35° 4' 0" S., long. 18° 37' 0" E., in 150 fathoms (several specimens). 
This species is distinguished from all its congeners by the dissimilar development 
and tuberculation of the right and left chelipedes. 1 
Pilumnoplax abyssicola, n. sp. (PI. XIX. fig. 2). 
The carapace is everywhere closely granulated, nearly glabrous, with a scanty 
pubescence near the margins. The front is about one-third the greatest width of the 
carapace, its anterior margin is straight, entire, without a median notch, and is not 
transversely sulcated; the antero-lateral margins of the carapace are shorter than the 
postero-lateral, and armed with three teeth behind the exterior angle of the orbit, which 
is not at all prominent; the first tooth is very small (on one side scarcely discernible), 
the second and third spiniform and acute; the postero-lateral margins are straight, and 
converge to the postero-lateral angles of the carapace; the orbital margins are entire; the 
inner subocular lobe is small and not prominent. The epistoma is very short and trans- 
verse ; the pterygostomian regions are finely granulated and somewhat pubescent; the 
post-abdomen of the male is triangulate, broad at the base, where it covers the whole of the 
sternal surface, its segments are distinct and short, the terminal segment subtriangulate. 
The eyes are borne on short, thick pedicels. The basal (or real second) joint of the 
peduncles of the antennae is rather slender, and does not reach the subfrontal process. 
The merus of the outer maxillipedes is nearly quadrate, distally truncated, and not pro- 
duced at the antero-external angle; the narrow straight exognath does not quite reach 
1 The foregoing description was drawn np, and the figure was outlined, before I had identified the Challenger 
specimens with Dr. Studer’s species, and both may still be useful for the identification of this remarkable deep-water 
form, which in the preliminary account of the Brachyura published in the Narrative of the Challenger Expedition 
I had designated Pseudorhombila ( Pilumnoplax ) mrmanni. 
