80 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
but sharp-pointed projecting rostrum; no postocular constriction. Chelipeds with arm and hand 
straight, sharply trigonal, the edges of these joints, as also outer edge of carpus, being very sharply 
and stoutly serrated. In the typical species the carapace is much flattened and the pterygostomian 
and subhepatic regions strongly excavated quite to the infero-exterior margin of the orbit, forming, 
when the chelipeds are retracted, covered afferent passages, the external apertures of which are seen 
between the base of the finger of cheliped and margin of orbit. 
Platylambrus serratus (Milne Edwards). 
Lamhrus serratus Milne Edwards, Hist. Nat. Crust., I, 357, 1834. 
Platylambrus serratus A. Milne Edwards, Crust. Reg. Mex., 156, pi. xxx, f. 1, 1878, and synonymy. 
Carapace about 1.5 times as broad as long, depressed; the furrow separating the gastric from the 
branchial regions is deep; elevations of the carapace ornamented with numerous unequal tubercles, 
some of which on the branchial region are sharp. Rostrum short and narrow. Antero-lateral margins 
cut into seven or eight triangular teeth, and terminating posteriorly in a large flat spine, directed 
nearly straight outward. Postero-lateral border armed with three short erect spines, the last of which 
limits the posterior border. A large median tubercle on posterior border. Chelipeds long (the length 
of arm equaling width of carapace without spines) and flattened; lower face smooth; outer margin 
cut into triangular, sharp teeth, of which nine, alternately large and small, are on the hand; teeth of 
inner margin smaller and more numerous (15 or 16 on the hand) ; upper surface showing a few 
tubercles on the hand, but more on the arm, where there is an obliquely longitudinal row. The first 
ambulatory leg does not reach end of arm; these legs are slightly spinulous, but in the main, smooth. 
Color, rosy gray, sometimes spotted with black; fingers carmine, teeth bordered with black (A. 
Milne Edwards). 
Dimensions of male: Length, 18.5 mm.; width, 27.8 mm. 
From North Carolina to Gulf of Mexico and West Indies, 5 to 30 fathoms. May ague/. Harbor, 1 
young male. 
Genus LEIOLAMBRUS A. Milne Edwards. 
Leiolambrus A. Milne Edwards, Crust. Reg. Mex., 148, 1878. 
Carapace hexagonal, considerably broader than long, with a strong spine near middle of its lateral 
margin. Surface depressed, smooth, or nearly so, with three low longitudinal elevations, one median, 
the others branchial. Front subtruncate, with a minute median point. Orbits with a closed fissure 
above, a large V-shaped fissure below toward outside, and an inner hiatus in which is lodged the 
antenna. Basal joint of antenna very small. Antennules 
folding almost longitudinally. Buccal frame narrowing a 
little forward, loosely covered by external maxillipeds; 
these last have an anteriorly tapering ischium, a merus 
with a semicircular antero-external outline, antero-internal 
angle rectangularly notched; merus and ischium of the 
endognath (not the exognath) bordered with long hairs 
which form a ventral covering to the afferent channels 
of the b ranch ue. Chelipeds very long, sharply trigonal, 
somewhat unequal; marginal teeth small and numerous. 
The fingers gape in the larger claw. First pair of ambu- 
latory legs the shortest. 
Leiolambrus nitidus, sp. nov. 
Carapace about three-fifths as long as broad, antero- 
lateral and postero-lateral margins subequal; the surface 
is coarsely punctate in elevated regions, smooth in depres- 
sions, a little granulous along summit of branchial, cardiac, and posterior part of mesogastric. Margin 
of front feebly tridentate, not advanced beyond antennular fossettes. Orbits wider than long and 
completely filled by large eyes. Antero-lateral margin obscurely toothed, the teeth having denticulate 
margins. Lateral spine strong, acuminate, directed either outward or somewhat backward, and 
slightly upward. A small tubercle on postero-lateral margin at end of branchial ridge. Extremities 
Fig. 12 . — Leiolambrus nitidus, male, x 2.5. 
