190 
THE VOYAGE OF H.M.S. CHALLENGER. 
(but not so greatly as in Thalamita), and their extero-distal angles are considerably pro- 
duced, the process thus constituted fills the interior hiatus of the orbit and thus excludes 
the flagellum from the orbit, and is usually in contact with the front. The ischium of 
the endognath of the exterior maxillipedes is not produced at its autero-internal angle ; 
the merus has its antero- external angle more or less produced, and rounded or subacute, 
it is distally truncated, and its antero -internal angle is obliquely truncated or slightly 
emarginate. The chelipedes (in the adult male) are subequal and often considerably 
developed, as in other Portunidse ; the joints are armed with spines ; the palms are often 
longitudinally costated on their exterior surface, and the fingers are straight and armed 
with unequal lobes or teeth on their inner margins. The ambulatory legs present 
nothing remarkable ; the merus-joints of the fifth (or natatory) legs are usually armed 
with a spine placed near the distal extremity of the inferior margin. 
The described forms are rather numerous and occur commonly in the littoral or 
shallow waters of the Indo-Pacific region, but I am not aware that any have been 
recorded from water of a greater depth than 50 fathoms. 
The following are species of this genus which have been described since the publica- 
tion of A. Milne Edwards’ Monograph in 1861 
Goniosoma hellerii, A. Milne Edwards. Indian Archipelago (Nicobars) ; New 
Caledonia. 
Goniosoma acutum, A. Milne Edwards. Japan. 
Goniosoma longifrons, A. Milne Edwards Samoan Islands, Upolu. 
Goniosoma acutifrons, de Man. Timor. 
Goniosoma spiniferum, Miers. North-East Australia, Port Molle ; South 
Formosa (Coll. Brit. Mus.). This species is perhaps a variety of Goniosoma 
variegatum: 
The Goniosoma dubium , of Hoffman, from .Reunion and Timor, is, according to de Man 
(Notes Leyden Mus., v. p. 151, 1883), identical with Goniosoma orientale, Dana. 
Goniosoma variegatum (Fabricius). 
Portunns variegatus, Fabricius, Entom. Syst. Suppl., p. 364, 1798. 
„ „ Milne Edwards, Hist. Nat. Crust., vol. i. p. 465, 1834. 
Charybclis variegatus, de Haau, Crust, in v. Siebold, Fauna Japonica, pp. 10-42, pi. i. 
fig. 2, 1835. 
Goniosoma variegatum, Miers, Proc. Zool. Soc. Lond., p. 33, 1879; Crust, in Rep. Zool. Coll. 
H.M.S. “ Alert,” p. 232, 1884, et synonyma. 
I have already, in the Report cited above, given a detailed description of the species 
I suppose to be Goniosoma variegatum (Fabricius). 
Certain specimens in the Challenger series apparently belong to a new variety of this 
form which I propose to designate : — 
