S'iG MR. E. J. MIEES ON THE 



compressed, tlie fifth somewliat raised upon the dorsal surface. 

 Type Oncinopus aranea, De Haau. 



This curious genus in the form of the basal antennal joint comes 

 nearest Macroclieira, and also has some afBnity with the Grrapsoid 

 genus Elamene and its allies. In the subdorsally elevated fifth 

 ambulatory legs it approaches the Maioid Anomura. 



§§ Sostrum sitiyple. 



*I]srACHOiDES, Ililne-Edivards {Xiplms, Eydoux & Souleyet). 

 Carapace triangular, with the regions well defined. No pra30cular 

 spine. Postocular well developed. Anterior legs with the palm 

 inflated. Ambulatory legs very slender, with the dactyli straight. 

 Type Inaclioidcs onicrorhynchus, M.-Edw. & Lucas. 



§§§ nostrum long, two-spined. 

 * Spines of rostrum contiguous ivith one another. 



EuRTPODius, Guerin-Meneville. Spines of rostrum rather 

 stout, narrowing to distal extremity. Ambulatory legs very long, 

 with the penultimate joint dilated and compressed. Type Eury- 

 podius Latreillei, Guerin. 



Oregonia, Dana. (Plate XII. figs. 3, 4.) Carapace flattened, 

 not spinose. Spines of rostrum very slender. Ambulatory legs 

 of moderate length, veiy slender, with the penultimate joint simi- 

 lar to the preceding, not dilated and comjpressed. Type Oregonia 

 gracilis, Dana. 



PLEiSTACANTnA, Mievs. Carapace convex, spinose. Spines 

 of rostrum long, divergent at their tips. Anterior legs in male 

 elongated. Ambulatory legs very slender and very long, penul- 

 timate joint not dilated and compressed. Type PleistacantJia 

 sancti-joJiannis, Miers. 



** Spines of rostrum divergent. 



1. Third joint of outer maxillipedes not emarginate at its distal end. 



Halimtjs, Latreille. Carapace subtriangular, with lateral mar- 

 ginal spines. Three spines above the eye. Merus joint of the 

 outer maxillipedes somewhat auriculated and produced at its 

 autero-external augle. Anterior legs in male enlarged, palm 

 slightly compressed. Ambulatory legs with the penultimate 



