in the Museum of the Smithsonian Institxdion. 113 



angles of the orbits ; teetli rather bhmt, equally prominent ; median 

 teeth smaller than the laterals, and separated from each other by a 

 much deej^er and narrower sinus than that separating them from 

 the laterals. Notch of orbital margin over base of antennae very 

 slight. Chelipeds rather long ; meros with four spines in front ; 

 inner spine of carpus about twice as long as basal spine of hand ; 

 hand of ordinary proportions, if anything rather more slender than 

 usual. A spine on meros joint of posterior feet. 



Dimensions of a male: Length of carapax, 0.40; breadth, 0.75 

 inch. The breadth in this and the two preceding species of Achelous 

 is measured between the tips of the lateral spines. 



It differs from A. acicminatus in its narrower carapax, shorter 

 lateral spines, blunter frontal teetli, and thicker hand. 

 Panama. Capt. J. M. Dow. 



Acheloii^ ancep^. 



Lupea anceps De Saussure, Crust, nouv. des Antilles, etc., p. 18 ; pi. ii, 

 f. 11. 



Ltipea JDuchassagni Desbomie et Schramm, Cnist. de la Guadeloupe, p. 39 ; 

 pi. iv, f . 25. 



Specimens from St. Thomas in the Smithsonian Collection 

 agree with the descriptions quoted above in everything except 

 their shorter chelipeds. 



OCYPODOIDEA. 

 Paclftvg^rapsiis gracilis. 



Metopogrwpsus gracilis De Saussure, Crust, nouv. des Antilles, etc. , p. 27 ; 

 pi. ii, fig. 15. 



Found at Barbados by Professor T. Gill. 



Pachygrapsus transversus. 



OrapsiLS tramversus Gibbes, Proc. Am. Assoc. Adv. ScL, 1850, p. 181. 

 Pachygrapsus tnmsversus Gibbes, loc. cit., p. 182. 



Metopograpsus dubius De Saussure, Crust, nouv. des Antilles, p. 29; pi. ii, 

 fig. 16. 



Found at St. Thomas by A. H. Riise, and at Barbados by 

 Theo. Gill. 



