REPORT ON THE BRACHYURA. 
281 
and merus-joints broader and shorter. The c-helipedes and ambulatory legs resemble 
those of Hymenosoma but the chelipedes are more robust and more strongly developed, 
with the palms more turgid, and the dactyli of the ambulatory legs are more distinctly 
falcated. 
The following forms seem to be referable to this genus, which is distinguishable from 
Hymenosoma and Hymenicus by the distinctly trilobated front, whose lobes are separated 
to the base : — 
Halicarcinus planatus. Common throughout the whole Antarctic Region. 
Halicarcinus ovatus, Stimpson. The representative on the Australian Coasts of 
Halicarcinus planatus. 
Halicarcinus lecichii, Nicolet. Chili. 
Halicarcinus lucasii, Nicolet. Chili. 
Halicarcinus planatus (Fabricius). 
Cancer planatus, Fabricius, Entom. Syst., vol. ii. p. 445, 1793. 
Halicarcinus planatus, White, Ann. and Mag. Nat. Hist., vol. xviii. p. 178, pi. ii. fig. 1, 1846. 
,, „ Milne Edwards, Ann. d. Sci. Nat., ser. 3, vol. xx. p. 222, 1853. 
„ „ Miers, Phil. Trans., vol. clxviii. p. 201, 1879, et synonyma. 
Hymenosoma planatum, Haswell, Cat. Australian Crust., p. 114, 1882. 
Specimens of this common and widely distributed inhabitant of the Antarctic or 
Austral region, and which is the only Brachyurous Decapod proper to that wide area 
of distribution, occurred at the following localities : — 
Between the Cape of Good Hope and Kerguelen (near Marion Island) on December 26, 
1873, in 50 to 75 fathoms (an adult female) ; off Prince Edward Island, 85 to 150 
fathoms (an adult female) ; at Kerguelen Island, in rock-pools (a male and a female) ; 
New Zealand, Cape Campbell (an adult male, from the Wellington Museum) ; Falkland 
Islands, 4 fathoms, in lat. 51° 32' 0" S., long. 58° 6' 0" W., Station 316 (five males 
and females) ; Port William (an adult male). 
One of the specimens from the Falkland Islands (Station 316) has the carapace 
somewhat more hairy and convex than is usual in the species. 
An adult male measures as follows : — 
Adult C • Lines. Millims. 
Length of carapace, about . . . . . .5 11 
Breadth of carapace, about ...... 6| 13 - 5 
(ZOOL. CHALL. EXP. — PART XLIX. 1886.) 
Ccc 36 
