GRAPSOIDEA. 



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to be the species so called by Owen in his account of the Crustacea of 

 the Voyage of the Blossom. ■ 



0. Urvillii, Guerin, Voyage de la Coquille, pi. 1, f. X; Owen, Voy. of the Blossom, 

 p. 80; Edwards, Crust., ii. 49. 



Ocypoda Gaudichaudii, Edw. and Lucas. 

 Valparaiso, Chili. 

 0. Gaudichaudii, Edwards and Lucas, D'Orbigny's S. A., p. 26, pi. 11, f. 4. 



Family III. GRAPSID^E. 



We have divided the Grapsidae into three subfamilies : — the inner 

 antennae exposed in a longitudinal sinus of the front characterize 

 one group, the Plagusinm; and the rest (having the same antennae 

 covered by the front), are divided according as the third joint of the 

 outer maxillipeds is crossed or not by a ridge (usually hairy) that 

 passes obliquely over the outer angle or outer surface of the second 

 joint; one division being the Grapsinai, the other the Sesarminai. The 

 existence of this oblique ridge, so well marke'd in Sesarma, has not in 

 all instances been allowed the authority of a generic characteristic. 

 Yet it seems to us that it should have even the higher importance, 

 here attributed to it. 



De Haan divides the genus Grapsus according to the form of the 

 third joint of the maxillipeds, his Grapsi (constituting a subgenus in his 

 system) having this joint scarcely longer than broad; and his Goni- 

 opses having this joint oblong, or as long as the second joint. The 

 former include in part the Cyclograpsi of Milne Edwards. A some- 

 what similar subdivision was subsequently made, by Dr. Randall, in 

 volume viii., pp. 124 and 126, of the Journal of the Academy of Natural 

 Sciences of Philadelphia, published in 1839. He retained for the 

 genus Grapsus, De Haan's Goniopsis, and called the species with the 



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