Notes on North American Crustacea. 225 



Cronius,* nov. gen. 



This genus is foimded on the Lupa rubra of M. Edwards, 

 which forms the connecting link between the old genus Lwpa^ 

 and Charyldis. It is allied to Charyhdis in the shape of the 

 front, and the movable part of the external antenna is some- 

 what remote from the orbit; but the process from the basal joint 

 of this antenna does not quite join the prseorbital tooth ; leav- 

 ing a narrow chink through which the movable part might 

 perhaps have access to the orbit. The basal joint of the antenna 

 is also armed with a short sharp spine beneath the articula- 

 tion of the movable joint. The antero-lateral margin is nine- 

 toothed, but the teeth are unequal, showing an approach to 

 Thalamita. Endostome as in allied genera. Meros joint of 

 the outer maxillipeds very little produced anteriorly ; external 

 angle rather prominent, projecting a little over the tip of the 

 exognath. Dactyli of ambulatory feet narrow and sulcated. 

 Abdomen of the male subtrianglar, sides a little concave. 



Croniuis ruber. 



Lupa rubra (Lam'k.) M. Edwards, Hist. Nat. des Crust, i. 454. 



This is one of the species common to both sides of the con- 

 tinent, specimens having been found at St. Thomas, by Mr. Riise, 

 and at Panama, by Mr. Sternbergh. 



Euphylax,f nov. gen. 



Carapax transversus, ovalis, convexus ; margine antero-laterali brevi, 

 rotundato, parce dentato ; regione faciei (inter angulos orbitarum exter- 

 nos), carapace vix qiiarta parte angustiore. Orbitae grandes, praelongae, 



* Kpdi/iof, nomen Neptuni. f Ev, bene, ^i\a^, Tigil. 



