REPORT ON THE BRACHYURA. 
223 
2. C a r c i n o p 1 a c i n se. 
Carcinoplacinse, Milne Edwards, Ann. d. Sci. Nat., ser. 3, Zool. xviii. p. 164, 1852. 
In this section the antero-lateral margins of the carapace are usually dentated or 
spinose, and the post-abdomen completely conceals the sternum at the base (except rarely 
in Pilumnoplax). 
The genera referred to the section Carcinoplacinse are : — Carcinoplax, Milne Edwards 
( = Curtonotus, de Haan) ; Pseudorhombila, Milne Edwards ; Geryon, Kroyer ( = Chalsepus, 
Gerstaecker) ; Eucrcite, de Haan; Litocheira, Kinahan ( = Bracliygrapsus , Kingsley); 
Pilumnoplax, Stimpson; Heteroplax, Stimpson; Bathyplax, A. Milne Edwards; Frevillea, 
A. Milne Edwards; and Camptoplax, Miers; also perhaps Catoptrus, A. Milne Edwards, 
and Libystes, A. Milne Edwards, -where the form of the post-abdomen in the male is not 
knowm, and Camptandrium, Stimpson, which is regarded by Dr. Stimpson as the type of 
a distinct family (Camptandriidse). 
3. Rhizopinse. 
Rhizopinse, Stimpson, Proc. Acad. Nat. Sci. Philad., p. 95, 1858. 
In this section the antero-lateral margins of the carapace are entire or subentire, and 
the post-abdomen in the male very rarely covers the whole width of the sternum at the 
base. The genera included in it are Scalopidia, Stimpson ( = Hypoplitlialmus , Richters) ; 
Rhizopa, Stimpson ; Typhlocarcinus , Stimpson ; Ceratoplax, Stimpson ; Notonyx , 
A. Milne Edwards ; Xenophthalmodes, Richters ; and perhaps Cryptocodoma , Miers. 
The species are all of small size and are almost exclusively Oriental or Indo-Pacific 
forms. 
Carcinoplacinse. 
Carcinoplacinse , Milne Edwards, Ann. d. Sci. Nat., ser. 3, Zool. xviii. p. 164, 1852. 
Geryon, Kroyer. 
Geryon, Kroyer, Nat. Hist. Tidskr., ser. 1, vol. i. p. 20, 1837. 
? Clialsepus, Gerstaecker, Arcliiv f. Naturgesch., vol. xxii. p. 118, 1856. 
Carapace cancroid in form, moderately convex, slightly broader than long ; the 
antero-lateral margins shorter than the postero-lateral margins, and armed normally 
with three spines, including the spine or tooth at the exterior angle of the orbit, which 
is sometimes less developed ; the intermediate spines (the second and fourth of the 
normal series) are sometimes present but rudimentary. Front slightly deflexed, of 
moderate width, and divided into two or four lobes or teeth. Epistoma short, transverse. 
The ridges of the endostome or palate are faintly indicated or obsolete (in the species I 
