218 
THE VOYAGE OF H.M.S. CHALLENGER. 
of Good Hope and West African coast, and thence to Ascension Island and Bermuda 
(see below). 
The following are species which have been described since Milne Edwards’ account of 
the genus in 1853 : — 
Geocarcinus planatus, Stimpson. California, near Cape St. Lucas. 
Geocarcinus depressus, Saussure. West Indies, Hayti. This species is perhaps 
not distinct from Geocarcinus lagostoma. 1 
Geocarcinus lagostoma ('?) (PL XVIII. fig. 2). 
? Geocarcinus lagostoma, Milne Edwards, Hist. Nat. Crust., vol. ii. p. 27, 1837 ; Ann. d. Sci. 
Nat., ser. 3, Zool. xx. p. 203, 1853. 
Two adult females, from Ascension Island, are referred to this species. 
The largest specimen has the following dimensions : — 
Adult $ . Lines. Millims. 
Length of carapace, . . . . . . . 33| 71 
Breadth of carapace, . . . . . . 43-1 92 
A small male from Bermuda differs so slightly from small examples of Geocarcinus 
lagostoma that I do not venture to separate it as a distinct species. It . is distinguished 
principally by the form of the merus of the outer maxillipedes, which, although notched 
as in Geocarcinus lagostoma, has the antero-external lobe less produced and rounded, so 
that the notch is more nearly terminal than in the specimens of Geocarcinus lagostoma I 
have examined. The spinules of the inferior margin of the penultimate joints of the 
ambulatory legs, which are well developed in small specimens of Geocarcinus lagostoma, 
are, in the specimen from Bermuda, nearly obsolete. In the coloration it nearly 
resembles specimens of Geocarcinus lateralis. 
This specimen may perhaps be referable to Geocarcinus depressus, Saussure, 2 in 
which, however, the maxillipedes (as figured) are of rather different form. 
The specimen from Bermuda is of the following dimensions : — 
6 ■ 
Lines 
Millims. 
Length of carapace, .... 
151 
32-5 
Breadth of carapace, 
181 
39 
Geocarcinus lagostoma has been but briefly described, and never, I believe, figured. 
I think it useful, therefore, to figure the adult female from Ascension Island in the 
Challenger collection, to facilitate its identification by future authors. The adult males 
1 Geocarcinus barbatus, Poeppig, from Chili, is thought by Milne Edwards (tom. cit., p. 205, 1853), to be a species of 
Gardiosoma ; Geocarcinus regius, Poeppig, also from Chili, is perhaps not a Geocarcinus. 
2 Vide Mdm. Soc. Phys. d. Geneve, vol. xiv., pt. ii. p. 439, pi. ii. fig. 14, 1858. 
