REPORT ON THE BRACHYURA. 
117 
on the upper surface ; fingers clentated on the inner margins and distally acute. The 
ambulatory legs are rather slender and the merus-joints are usually, but not invariably, 
spinuliferous or denticulated above. 
This genus is very nearly allied to Halimede (cle Haan), but is distinguished, as 
M. A. Milne Edwards has noted, by the coalescence of the third to the fifth post-abdominal 
segments. 
O 
The following species have been referred to this genus : — 
Medseus ornatus, Dana. Hawaiian Islands. 
Medseus elegans, A. Milne Edwards. New Caledonia. 
Medseus nodosus, A. Milne Edwards. New Caledonia and Lifou Islands. 
Medseus spinimanus (Milne Edwards) = Cancer miniatus, Desbonne and Schramm, 
fide, A. Milne Edwards. Guadeloupe. 
Medseus haswelli, n. sp. Australia, Twofold Bay, 150 fathoms. 
Medseus simplex, A. Milne Edwards. Madagascar and Samoa Islands (Upolu). 
Medseus haswelli, n. sp. (PI. XI. fig. 2). 
The carapace is slightly transverse, rather flat, with the sutures defining the various 
regions of the dorsal surface very distinct ; the body is everywhere very distinctly and 
evenly granulated ; the granules of the dorsal surface somewhat larger and less crowded 
than those of the inferior surface of the body. The antero-lateral margins of the carapace 
are somewhat shorter than the postero-lateral margins. The front is rather broad and 
but little prominent ; its anterior margin is obscurely sulcated longitudinally and 
divided into two lobes by a slight median notch ; the antero-lateral margins of the 
carapace bear only three triangular teeth, the first of which is placed at some distance 
from the exterior orbital angle, and the second rather nearer to the third than to the 
first tooth. The infra-orbital prolongations of the antero-lateral margins, characteristic of 
the type of the genus ( Medseus ornatus ) are here indicated merely by a very obscure line 
of granules, reaching from the first of the antero-lateral teeth to a point just beneath the 
exterior angle of the orbit. The orbits are oval, with a moderately prominent inner 
suborbital lobe and a slightly indicated notch at the outer angle, and another in the middle 
of the superior margin. The post-abdomen in the male is five-jointed (as in the type), with 
the third to the fifth joints coalescent, and the terminal joint transverse and semicircularly 
rounded. The antennae and maxillipedes present nothing remarkable ; the basal antennal 
joint reaches to the infero-lateral frontal process, and the exognath of the outer maxillipedes 
attains the antero-external angle of the distally truncated merus-joint. The chelipedes 
are moderately robust for so small a species, the joints granulated much more distinctly 
on the outer than on the inner surface ; the merus-joint has a series of larger granules on 
its upper margin, and the carpus a spiniform tooth on its inner surface ; the palm of the 
