Boone, Crustacea, Cruises of "Eagle" and "Ara," 1921-28 219 



three-fourths as long as. the merus. The dactyl is approximately as 

 long as the propodus and is very slender, acuminate and carinated. 

 The depressions between the carinae are setiferous. The second pair 

 of legs is the longest, exceeding the first pair by slightly more than 

 one-half the length of the dactyli, and the third pair by about one- 

 third the length of the dactyli; the fourth pair are much smaller, 

 reaching only halfway the propodus of the third pair. All ambulatory 

 legs are heavily fringed with long, light yellow hairs. 



There is a small, round branchial aperture situated between the 

 bases of the third and fourth legs which have the posterior surface of 

 the basal joint of the third leg closely appressed to the anterior sur- 

 face of the basal joint of the fourth leg, both of these surfaces are 

 flat and closely opposed; their distal margin is bordered by a dense 

 fringe of setae, which appear to have an olfactory function. This 

 aperture opens into the branchial cavity behind a rounded tubercle 

 which is situated above the third leg, where a branchia is absent in 

 Ocypode. Over this aperature a complete tube is formed by ridges 

 which arise above the articulation of the legs and by the projection 

 of the carapace. "Water passes inward through these apertures, over 

 the gills and out through the frontal aperture. 



Synonymy. — Cancer arenarius Catesby, Nat. Hist. Carolina, vol. 2, p. 

 35, pi. 35, 1743. 



Cancer vocans Linnaeus, Sys. Nat. ed. 10, vol. 1, p. 626, part, 1758. 



Cancer quadratus Fabricius, Mant. Ins., vol. 1, p. 315, 1787; Ent. 

 Syst, auct. et emend., vol. 2, p. 439, 1793. 



Ocypode quadrata Fabeicius, Ent. Syst. Suppl., p. 347, 1798. 



Ocypode rhomlea Fabricius, Ent. Syst. Suppl., p. 348, 1798. 



Ocypoda albicans Bosc, Hist. Nat. Crust., vol. 1, p. 196, and X, 

 1801-02. — Latreille, Hist. Nat. Crust., vol. 6, p. 48, and XI, 

 1802-03.— Eathbun, Proc. Wash. Acad. Sci., vol. 2, p. 134, 1900; 

 BuU. 97, U. S. Nat. Mus., p. 367, pis. 127 and 128, 1917 ; Rapport 

 betreffende een vooloopig onderzoek naar den toestand van de 

 visscherij en de Industrie van zeeproducten in de Kolonie Curagao, 

 vol. 1, p. 342, 1907. 



Ocypode arenarius Say, Journ. Acad. Nat. Sci. Phila., vol. 1, p. 69, 

 1817. 



Monolepis inermis Say, op. cit., p. 187. 



