8 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
superior orbital surface or eyebrow shallow, not varying much in length throughout its width; margins 
finely granulate. Inferior margin of orbit with large truncate tubercles, increasing in size and distance 
apart toward the outer extremity. 
Large cheliped very heavy. Merus and carpus elongate, thick, rugose on the outer surface, and 
without armed margins. Outer surface of palm coarsely tuberculate on its upper half, the tubercles 
gradually becoming fine granules below; upper and lower margins set off by deep grooves. Inner 
surface of palm with a ridge marked by a single line of large tubercles, leading obliquely upward from 
the lower margin to the carpal cavity, where it turns at a little less than a right angle and is continued 
less than halfway to the upper margin, or when continued farther the tubercles are obsolete. On the 
palm at the base of the dactylus are two tuberculate lines, the distal one very short; both are slightly 
oblique to the lower margin. In full-grown males the fingers are very long, the lower margin of the 
propodus sinuous, the pollex bent down for its distal third. The dactylus equals or overreaches the 
pollex. The prehensile tubercles are irregular, but not strikingly so. The dactylus is roughened at 
its base on the upper side and has a short longitudinal groove on the outer side below the upper margin. 
The smaller cheliped is rather long, the fingers longer than the palm and somewhat gaping to the tips. 
Meral joints of ambulatory legs dilated and very broad, especially those of second and third pairs. 
Old males show a tendency to widen behind the antero-lateral angles; this tendency is stronger 
on the side of the large claw. In males which are young or have not reached their fullest development 
the pollex of the large chela is straight, not bent down, and the lower margin of the propodus is 
convex, not sinuous. The meral joints of the ambulatory legs are wider in the female than in the 
male, as is the case in other species of the genus. 
Male, length, 17.2 nun.; width, 27.5 mm. 
Jamaica; Brazil at Natal, Rio Grande do Norte, also Rio Parahyba do Norte, Sad Matheos and 
Victoria. Porto Rico: Rio Bayamon above Palo Seco, 2 adult males with straight propodi, 1 adult 
female; Fajardo, 1 male, 1 female, both small but mature, large cheliped of male missing. 
Genus EURYPLAX Stimpson. 
Euryplax Stimpson, Ann. Lyc. Nat. Hist. N. Y.,vn, 00, 1S59; Bull. Mus. Comp. Zoo!, n, 150, 1871. 
Carapace transverse, broad; antero-lateral margin very short, dentate; front nearly half as broad 
as the carapace; ocular peduncles of moderate length; antennal flagellum excluded from the orbit by 
a process of the basal joint, which joins the front. Palpus of the endognath of the outer maxillipeds 
articulating with the merus at its inner angle. 
Verges of the male arising from coxte of fifth pair of feet and passing through canals in the 
sternum. Sternum partially exposed in the sinus of the abdomen between its second and third 
segments. All the segments of abdomen distinct. Chelipeds heavy, not very unequal. 
Only one species known from West Indian region, viz, E. nitida Stimpson, the type of the genus. 
Euryplax nitida Stimpson. 
Euryplax nitidus Stimpson, Ann. Lyc. Nat. Hist.. N. Y., vii, CO, 1859; Smith, Trans. Conn. Acad. Soi., n, 162, 1870. 
Euryplax nitida Stimpson, Bull. Mus. Comp. Zool., ii, 150, 1871; Kingsley, P’roc. Acad. Nat. Sci. Pliila., xxxi, 399, 1879. 
Carapace smooth and shining, convex fore and aft, as well as from side to side; antero-lateral 
margin less than half as long as the postero-lateral, and armed with three strong teeth including the 
angle of the orbit; carapace widest at the third tooth. Front deeply notched on each side at the 
insertion of the an ten me; inter-antennal margin nearly straight. Chelipeds in the male with a round 
pit at anterior distal corner of lower surface of merus; this pit is surrounded by a fringe of long hair; 
a sharp curved spine near the distal end of the upper surface of the merus. Carpus with a sharp inner 
spine; inner surface pilose. Ambulatory legs slender. Carapace of female narrower. Chelipeds more 
nearly equal. Merus without pit and surrounding hair. 
The dimensions of two specimens are as follows: 
Width 
Width 
Sex. 
Locality. 
Length. 
at third 
tooth. 
at orbital 
tooth. 
Male. 
Cedar Keys, Fla 
15 
24.9 
20.8 
Fern. 
Marco, Fla 
15 
24 
20.8 
West coast of Florida and Florida Keys to 49 fathoms (Stimpson); St.Thomas (Stimpson). Off 
Vieques, 14 fathoms, coral, sand, shells, station 6085, 1 small male. 
