318 BULLETIN 152, UNITED STATES NATIONAL MUSEUM 



Taboga Island, Panama Bay; undet stones at low tide; May, 1927; 

 Melbourne Ward; 1 female; returned. 



Porto Bello, Panama (Atlantic side); living on large holothurian; 

 1912; August Busck; 2 ovigerous females (50967). 



Salinas, Ecuador; September 13, 1926; W. L. Schmitt; 1 young 



(60757). 



Genus METOPOCARCINUS Stimpson 



Metopocarcinus Stimpson, Ann. Lye. Nat. Hist. New York, vol. 7, 1860, p. 216 

 [88]; type, M. truncatus Stimpson. 



Carapace bare, suborbicular or subhexagonal, an- 

 teriorly truncate; regions faintly indicated; antero- 

 lateral margins almost entire, shorter than postero- 

 lateral, somewhat cristate, crest posteriorly curved 



Figure 48.— Metopo- . ■ n-i • i i 



cARciNus TRUNCATUS, mward as m Pilumnoides. Front large, very wide, 

 MALE, Cape San prominent, margin straight, subentire. Orbit com- 



LUCAS, CARAPACE 0.18 ,,^.1111,1 



INCH WIDE, DORSAL plctcly iiLled by the large eye. Antenna occupying 

 view. After stimp- ^j^q inner hiatus of the orbit, basal article not 



SON . . . 



reaching front. Feet of medium size. Third, 

 fourth and fifth segments of male abdomen fused (Stimpson). 

 Known only from a single species. 



METOPOCARCINUS TRUNCATUS Stimpson 



Plate 148, Figures 1 and 2 



Metopocarcinus iruncatvs Stimpson, Ann. Lye. Nat. Hist. New York, vol. 7, 

 1860, p. 216 [88], pi. 3, fig. 4 (type-locality, Cape St. Lucas; type not extant). 



Diagnosis. — Carapace narrow, hexagonal-orbicular, nearly smooth. 

 Front prominent, truncate. Lateral teeth obscure. 



Description. — Carapace somewhat convex, naked, nearly even, 

 finely granulate, granules rather sparse but symmetrically arranged 

 especially on the raised portions. Antero-lateral margin obscurely 

 dentate, five teeth or divisions are evident: A small pointed tooth 

 at orbital angle, followed by two shallow lobes, the third longer than 

 the second; the fourth division is a tooth at the widest part of the 

 carapace; behind it an obscure tooth whence the marginal crest curves 

 inward. Front double-edged, the edges granulate, lower margin not 

 visible from above and separated by a sulcus from the upper; the 

 latter is straight, transverse, a feeble nick at its middle. Orbit with 

 two closed fissures above, and a shallow lobe at the middle of the lower 

 margin; inner angle sharp. Eyes large, filling orbits. Basal article 

 of antenna narrow, reaching just as far forward as the inner sub- 

 orbital tooth; next article reaching the prolongation of the front. 

 Merus of outer maxillipeds narrower than ischium, distal margin 

 oblique, outer angle arcuate, distal inner margin slightly notched. 

 Chelipeds and legs naked, unarmed; chelipeds sparingly finely granu- 

 late; carpus uneven, a short tooth at inner angle; palms inflated; 

 fingers gradually tapering, acuminate; major dactylus with a large. 



