THE BEACH YURA AND MACRURA OF PORTO RICO. 
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Stenocionops furcata (Olivier). 
Cancer fur calus Olivier, Encyc. M6th., Hist. Nat., Insectes, vi, 174, 1791. 
Cancer cornudo Herbst, Natur. Krabben u. Ivrebse, m, pt. 4, p. G, pi. ltx, f. 6, 180-1. 
Pericera cornudo Latreille, Cuvier’s Regno Anim., cd. 2, iv, 59, 1829. 
Stenocionops furcata Rathbun, Ann. Inst. Jamaica, i, 6, 1897. 
Body and feet covered with dark brown hairs, some of which are stiff and hooked. Carapace 
not very uneven; some rounded prominences on gastric and cardiac regions; this last also with two 
median projections, the first very small ; the other, large, suberect, and curved, overhangs the posterior 
border. Frontal horns large, very divergent at base; distally often subparallel or even somewhat 
converging; on each side a superior orbital spine. The lateral margins bear, besides the very sharp 
external orbital angle, four very large, sharp spines, one hepatic and three branchial. Basal article of 
antenna armed in front with a spine which does not reach beyond orbital border. 
The c.helipeds attain in the male a considerable size and are nodose; arm spined above; hand long, 
cylindrical, and granulate. Fingers about half as long as palm, gaping for their basal half; a tooth on 
dactylus near its base. 
Length of large male from tip of rostrum to tip of posterior spine, 146.5 mm.; width, including 
spines, 93 mm.; length of rostrum, about 53 mm.; length of cheliped, 215 mm. 
Mayaguez Harbor, 25 to 30 fathoms, station 6062, 2 large males, 1 large female; off Punta de 
Melones, 7* fathoms, station 6072, 1 young specimen; Ensenada Honda, Culebra, 1 young specimen; 
iiff Vieques, 14 fathoms, station 6085, 1 very young. San Juan (Gundlach). Ranges from Georgia to 
Bahia, Brazil. 
Stenocionops furcata coelata (A. Milne Edwards). 
Pericera ccdata A. Milne Edwards, Bull. Soc. Philom. (7), ii, 224, 1878. 
Pericera aetata A. Milne Edwards, Crust. R6g. Mex., 200, pi. xv A, f. 3, 1879. 
Pericera cornula cxlata Rathbun, Proc. U. S. Nat. Mns., xv, 244, 1892. 
Differs from typical form of species in its more uneven carapace, in the greater divergence of the 
horns, which are straight, and in the relatively greater width across orbits. Not very sharply set off 
from S. furcata. 
Gulf of Mexico and Caribbean Sea, 21 to 175 fathoms. Off Vieques, 15 fathoms, station 6091, 
one male. It is possible that some of the young specimens enumerated under S. furcata belong here. 
Genus MACROCCELOMA Miers. 
Macroccdoma Miers, Jour. Linn. Soc. London, xiv, 665, 1879. 
Carapace subpyriform, but broadened anteriorly by projecting orbits; dorsal surface unarmed, or 
tuberculated, or with a few long spines; margins without a series of elongated lateral spines, but often 
with a strongly developed lateral epibranchial spine, preceded by some smaller spines. Spines of 
rostrum well developed. Eyes retractile within roomy projecting tubular orbits. Antennae have the 
basal joint considerably enlarged and armed distally with one or two spines. Mobile portion of antenna 
sometimes concealed by rostrum, sometimes exposed. Merus of external maxillipeds broader than 
ischium and notched at internal angle for insertion of palp. The chelipeds in the male have the palms 
enlarged and the fingers either arched and meeting onlyat tip, or in contact throughout. Ambulatory 
legs rather short. 
Key to the Porto Rican species of the genus Macrocceloma. 
A. Basal antennal joint with one spine. 
B. Carapace without a strong transverse spinous and tuberculated ridge connecting epibranchial spines. 
C. Rostral horns separated at base by a narrow sinus. 
D. Antennal spine large. Epibranchial spines short, broad, and blunt trispinosum 
D'. Antennal spine small. Epibranchial spines longer, acute diacantlmm 
C'. Rostral horns separated at base by a broad U-shaped sinus diplacanthum 
B'. Carapace with a strong, transverse, spinous and tuberculated ridge connecting the epibranchial spines., mbparallelum 
A'. Basal antennal joint with two spines concavum 
