Z oolozy. 285 
ilipeds. "The former are De Haàan's Grapsi, and RandalUs Pachy- 
grapsi; the latter De Haan's Goniopses and Randall's Graps?. But 
the length of this joint, as we have shown in many other cases, is à 
characteris!ic of small importance, and such a basis for subdivision is 
therefore wrong. "lhere are two natural groups; one with arcuate 
sides, like G. pictus, and the other with straight sides like G. cruenta- 
tus and G. messor ; and in each, this joint may be short or oblong. 
G. variegatus, like G. picius, has the joint oblong; yet a species 
every way similar and hitherto referred to the cariegatus has the same 
joint not longer than broad.* ^ We hence reject this subdivision and 
adopt two others, viz: Grapsus, having arcuate sides, and Goniograp- 
sus, having straight sides. "The latter forms the transition to Sesarma 
and G. cruentatus ls like the Sesarme in habit. 
The genus Cyclograpsus of Edwards is characterized by its author 
as having a piliferous crest on the outer maxillipeds, though exceptions 
are admitted. Subsequently, M'Leay made his genus Gnathochasmus 
on the same type. Some recent authors have taken M'Leay's name 
for these typical species and restricted Cyclograpsus to the exceptions. 
We find no authority in the rules laid down by the British Association, 
or in the nature of the case, for thus perverting Cyclograpsus from its 
P type as. first established, and we therefore make Gnathochasmus 
| synonym of it, and adopt a new name for the species without the 
piliferous crest. "This we believe is due to M. Edwards. 
The following is a synopsis of the Families, Subfamilies and Genera 
of Grapsoidea :— 
CRUSTACEA GRAPSOIDEA. 
1l. ARTICULUS MAXILLIPEDIS EXTERNI ÁTUS ANGULO 9OTII INTERNO 
ARTICULATUS. | 
Fax. I. GONOPLACIDJE. 
Carapax transversus. Frons quartá parte latitudinis carapacis longior, 
paulo deflexus, lamellatus. Antenns internzg transversze. Articulus 
abdominis maris 2dus sterno contiguo angustior. 
G. 1l. EvcnarE, De Haan.t—Carapax antice arcuatus, parce de- 
clivis, Panopeo formá antennisque affinis. Appendices maris 
sexuales e sterno orte abdomineque tectce. — Pedes maris antici 
| . breves, crassi. Oculi breves. Abdomen maris 5-articulatum, 
versus basin sterno contiguo vix angustius. 
G. 2. Cunroworus, De Haan.j—Carapax antice arcuatus, parce 
declivis, margine antero-laterali rotundato. Appendices maris 
sexuales e basi pedum ortze, in canaliculo sterni ducte, deinde 
abdomine tectze. Oculi breves. Pedes maris antici preelongi. 
* 'The species referred to is one from Valparaiso. The G. variegatus, according 
to its description by Edwards, and the figure by Guerin, has the joint quite oblong. 
The Valparaiso species, which we name the Grapsus planifrons, has this joint no 
longer than broad. 
1 Crust. Faun. Japon, p. 36. G'eryon, Króyer, Tidskrift, i, (183'7,) p.15, pl. 1. 
1 De Haan, Crust. Faun. Japon, p. 20. .JPseudorhombila, Edwards, Crust. ii, 68. 
