286 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.xxii. 



C. Antero-lateral margin ending at the orbit. 



D. Ambulatory legs cristate Lophopanopeus. 



D'. Ambulatory legs not cristate. 



E. Carapace deeply lobulate Actwa. 



E'. Carapace not deeply lobulate. 



F. Fingers sharp-pointed ; carapace subhexagonal Xantho. 



F'. Fingers blunt-pointed, hollowed at the tip. 

 G. Carapace very broad, oval; antero-lateral margin thickened. 



Xmithodius. 

 G'. Carapace of moderate width, suboval; front and antero-lateral mar- 

 gins not thickened Leptodius. 



B'. Fronto-orbital border much more than half the greatest width of the carapace. 

 C. Fingers pointed at tips. 



D. Carapace and legs granulate or tuber culate Xanthias. 



D'. Carapace almost smooth, except for short transverse lines. Legs smooth. 



Eupanopeus. 



C. Fingers hollowed at tip Chlorodiella. 



A'. The ridges that deline the efferent branchial channels extend to the anterior 

 boundary of the buccal cavern, and are often very strong. 

 B. Fronto-orbital borders half or less than half the greatest breadth of the cara- 

 pace, which is broad and transversely oval Epixanthus. 



B'. Fronto-orbital border just about two-thirds the greatest breadth of the cara- 

 pace. Antero-lateral borders almost always shorter than the 

 postero-lateral Pilumnus. 



Genus ACT^^A de Haan. 



ACT.^A MARGARITARIA A. Milne-Edwards. 



Actoea margaritaria A. Milne-Edwards, Nouv. Arch. Mus. Hist. Nat. Paris, IV, 

 1868, p. 62, pi. XVII, figs. 9-12. 



West African localities. — Cape Verde Islands (A. Milne-Edwards); 

 logo-logo, St. Thomas (Osorio). 



Genus XANTHO Leach. 



KEY TO THE WEST AFRICAN SPECIES OF THE GENUS XANTHO. 



A- Carapace wide ; width more than 1;^ its length rivulosus. 



A'. Carapace narrow ; width less than 1^ its length pilipes. 



XANTHO RIVULOSUS (Risso). 



Cancer rivulosus Risso, Crust. Nice, 1816, p. 14. 



Xantho rivulosus Milne-Edwards, Hist. Nat. Crust., 1,1834, p. 394. 



Range. — Great Britain ; Atlantic coast of Europe; Black Sea; Medi- 

 terranean Sea; West coast of Africa. 



West African locality. — Angola (Osorio). 



XANTHO PILIPES A. Milne-Edwards. 



Xantho pilipes A. Milne-Edwards, Ann. Soc. Entom. France, VII, 1867, p. 268. 

 XarJho pilipes? Miers, Ann. Mag. Nat. Hist. (5), VIII, 1881, p. 213, 



West African localities. — Senegal (A. Milne-Edwards); Goree Bay, 

 Senegambia, 9 to 15 fathoms (Miers); Senegambia (Ortmann). 



