74 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
Macrocceloma trispinosum (Latreille). 
Pisa trispinosa Latreille, Encyc. Moth., Hist. Nat., x, 142, 1S25. 
Pcricera trispinosa Gufirin, Icon. Crust., pi. 8, f. 3; A. Milne Edwards, Crust. Reg. Mex., 52, pi. xv, f. 2, 1873. 
Macrococloma trispinosa Miers, Jour. Linn. Soc. London, xiv, 6G5, 1S79. 
Body and feet covered with very short, brown hairs which form a sort of velvet. Carapace thick 
and very swollen, wide at line of orbits, narrowing in hepatic portion, widening again posteriorly. 
The gastric region bears posteriorly a large rounded tubercle, little prominent. Some protuberances of 
similar nature on epibranchial lobes and on anterior cardiac lobe. Front formed of two flattened 
horns which at first are parallel, but separate gradually toward extremity. Inner angle of basal article 
of antenna surpasses greatly the frontal margin, and forms, on each side of rostral horns, a broad spine 
directed obliquely outward; flagellum small and hidden under front. Metabranchial lobes prolonged 
laterally in a strong, flattened spine directed outward and a little backward. A similar but smaller 
projection on middle line of posterior margin. Chelipeds of male not strong; arm long, nodose; hand 
relatively short; movable finger lightly furrowed above. Ambulatory legs short, feeble, and a little 
nodose. Length of male, 44 mm.; width, 40.5 mm. 
From North Carolina to Bahia, Brazil; Bermudas. Porto Rico: Mayaguez Harbor; off St. Thomas, 
20 to 23 fathoms, station 6079; off Culebra, 15J- fathoms, station 6087; Ensenada Honda, Culebra; 
Aguadilla (Gundlach). 
Macrocceloma subparallelum (Stimpson). 
Periccra subparallela Stimpson, Ann. Lye. Nat. Hist. N. Y., yn, 182, 1860; A. Milne Edwards, Crust. R6g. Mex., 54, pi. xm, 
f. 3, 1873. 
Macrococloma subparallela Miers, Challenger Rept., Zoo]., xvn, 79, 1886. 
Carapace less swollen and less thick than in M. trispinosum, covered, as well as feet, with a short, 
yellowish pubescence, in the midst of which are some longer, stiff, and hooked hairs, forming a border 
beginning at extremity of rostral horns and continued to branchial regions. Rostral horns almost 
parallel, curving down a little and separated to base by a wide, deep sinus. Inner angle of basal joint 
of antenna much smaller than in M. trispinosum and scarcely visible outside the rostral horns; flagellum 
small and entirely concealed. Hepatic regions more swollen than in M. trispinosum; metabranchial 
lobes produced outward and backward in two triangular spines, connected by a transverse line of 
elevations on branchial and cardiac regions, which increase in prominence and sharpness with age. 
The sternum bears some transverse, oval depressions on each article. Chelipeds strong, hand short 
and high. Ambulatory legs small. 
Dimensions of male: Length, 40 mm.; width, 35 mm. 
West Indies. Porto Rico: Guanica Bay, on coral reef; Playa de Ponce Reef; Fajardo. 
Macrocceloma diacanthum (A. Milne Edwards) . 
Periccra dicantha A. Milne Edwards, Crust. Rdg. Mex., 57, pi. xv, f. 3, 3875 ( diacantha on plate). 
Macrococloma diacantha Miers, Challenger Rept., Zool., xvn, 79, 1886. 
This species is intermediate between M. trispinosum and M. diplacanthum; it differs from the first 
in its longer, sharper, and more divergent horns, in its well-developed and very sharp postero-lateral 
spines, in the sharp spine on the posterior part of the urocardiac lobe, and in the width of the basal 
article of the external antennae. It differs from M. diplacanthum in the divergence of the rostral horns, 
in the short spines on the margin of the orbit in front and behind, and in the character of the lateral 
horns, which are not enlarged at their extremity. 
Dimensions of male: Length, 33.7 mm.; width, 29 mm. 
Majores, 12 fathoms; Kingston Harbor, Jamaica; off Cape St. Roque, Brazil, 20 fathoms. Off 
Boca Prieta, Porto Rico, 8J fathoms, station 6075. 
Macrocceloma diplacanthum (Stimpson). 
Periccra diplacantha Stimpson, Ann. Lyc. Nat. Hist. N. Y., vn, 183, 1860; A. Milne Edwards, Crust. R6g. Mex., 55, pi. xm, 
f. 2, 1873. 
Macrococloma diplacantha Miers, Challenger Kept., Zool., xvn, 79, 1886. 
Allied to M. subparallelum. The carapace, however, is narrower, more swollen, and the tubercles 
on the gastric, branchial, and cardiac regions are more clearly marked; rostral horns longer and more 
slender. Inner angle of basal article of antennse shorter, so that it does not show in front of orbit. 
Orbits tubular; outer margin entire. Lateral spines of carapace wide, lamellar, bifid at their extremity, 
