60 
BULLETIN OE THE UNITED STATES FISH COMMISSION. 
Epialtus bituberculatus Milne Edwards. 
Epialtus bitnberculalus Milne Edwards. Hist. Nat. Crust., r, 815, pi. xv, I. 11, 1834; A. Milne Edwards, Crust. Reg. Mex., 139, 
]il. XXVII, figs. 1, 2, and 3, 1878, and synonymy; Rathbun, Proc. U. S. Nat. Mus., xvn, 1894, 07. 
Epialtus sulcirostns Stimpson, Ann. Lye. Nat. Hist. N. Y., vn, 198, 1800; A. Milne Edwards, Crust. Reg. Mex., 141, pi. xxvri, 
f. 6, 187S. 
tEpialtm laupiroslris Stimpson, Ann. Lye. Nat. Hist. N. Y., vu, 199, 1800; A. Milne Edwards, Crust. E<?g. Mex., 141, pi. xxvn, 
f. 5, 1878. 
? Epialtus minimus Loekington, Proe. Cal. Acad. Sei.. vn, July 17, 1870, p. 77 (15), 1877. 
Epialtus dilntatus A. Milne Edwards, Crust, Reg. Mex., 140, pi. xxvn, !'. 4, 1S78. 
Carapace subpentagonal, with two tubercles on gastric region and two lateral teeth or lobes very 
variable in shape and relative size. In the typical form the lobes are separated by a shallow sinus, 
the carapace is distinctly widest at the posterior lobe, the rostrum is triangular, obtuse and entire. In 
the varieties the width at the hepatic region may equal that at the branchial region, the anterior lobe 
is much more prominent and may be either broad and obtuse or narrow and spiniform. Sometimes 
one lobe or both has a tubercle on its anterior margin. The rostrum varies in length and shape, and 
may be either triangular or oblong, and entire or emarginate, sometimes constricted near the base. In 
the typical form the preorbital teeth are obsolete, but are present, though small, in some of the varieties. 
Postorbital tooth wanting. Abdomen of male with fourth and fifth segments fused. 
Chelipeds variable; propodus in typical form wide, of moderate length, widening slightly toward 
the distal end; dactyl us with a tooth near its base; in the varietal forms the hand may be cristate and 
widening rapidly toward the lingers. The propodi of the ambulatory legs have a tuft of setse on the 
under side proceeding from a slight prominence nearer distal than proximal end, but are without the 
strong tooth near base represented in the description and figure of E. brasiliensis given by Dana. 
In 1894 ( loc . oil.) I gave in detail the variations in the specimens in the National Museum, and I 
incline to think that the species is subject to as much variation as is Menxthim monoceros Latreille, six 
varieties of which are given by Dana under as many specific names. 
Dimensions: Puerto Real, male, length, 9.6 mm.; width, 8 mm.; ovigerous female, length, 7.1 
mm.; width, 6 mm. 
From Indian River, Florida, to Rio de Janeiro; from Southern California to Chile. Porto Rico: 
Mayaguez, 1 female (near the longirostris form); Puerto Real, 1 male, 1 female, 1 juv. (dilatatus form) ; 
Arroyo, 1 male, 6 juv. (bras Mens is form); Ensenada Honda, Culebra, 1 male (near the longirostris 
form); Fajardo, I female ( brasiliensis form) . 
Genus ACANTHONYX Latreille. 
Acuiilhony. r Latreille, Eneyc. Moth., Hist. Nat., Inseetes, x, 698, 1S25. 
Carapace elongate, almost smooth, lateral margins toothed, the anterior tooth much enlarged. 
Rostrum with two flattened divergent horns. Orbits small, entirely filled by the large eye peduncles. 
A preorbital tooth. An ten me visible at the sides of the rostrum. Merus of outer maxillipeds trans- 
verse, dilated at the antero-external angle, notched at the antero-internal angle. Legs short, rather 
stout. Chelipeds in male enlarged. Ambulatory legs decreasing in length successively from first to 
fourth pair, compressed; propodi dilated, the posterior margin concave and setose near end, at broadest 
part forming a blunt tooth against which the dactylus fits like a claw; dactyl i spinous on their inner 
margin. Abdomen of male with six or seven segments. 
Acanthonyx petiverii Milne Edwards. 
Acanthnnyx petiverii Milne Edwards, Hist, Nat. Crust., I, 343. 1834; Dana, Crust. U. S. Expl. Exped., I, 128, pi. V, f. 6, 1852. 
Aonvlhonyx emarginatus Milne Edwards & Lueas, d’Orbigny's Voy. l’Amer. Merid., vr, pt. 1, p. 9, 1S43; rx.pl. v, f. 2,1847. 
Aemittioni/x debills Dana, Am. Jour. Sci. (2), XI, 272, 1851; Crust. U.'S. Expl. Exped., I, 127, 1852; pi. v, t. 5, 1855. 
Carapace oblong, antero-lateral angles subrectangular, obtuse, frontal region triangular. Two 
small teeth on margin of branchial region. Carapace almost smooth; three obscure setiferous tubercles 
on gastric region, one on the cardiac, and one on the intestinal region; these tubercles are obsolete in 
the female, but the setce remain. Lateral teeth and rostrum setiferous. Rostrum short, deflexed, 
bifid. Preorbital lobes obtuse, elevated. No postorbital tooth. Basal joint of antenme unarmed, the 
second and third joints subeylindrical, attaining end of rostrum; flagellum very slender. Chelipeds 
with merus subtriangulate; carpus with an external crest and two or three setiferous tubercles; manus 
