THE BRACHYURA AND MACRURA OF PORTO RICO. 
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Mithrax sculptus (Lamarck). 
Maia sculpta Lamarck, Nat. Hist. Anim. sans Vert., v, 242, 1818. 
Mithrax sculptus Milne Edwards, Mag. Zool., ii, pi. v, 1832. 
Carapace broader than long, with rounding margins. Front broad, little advanced, formed of 
two small tubercles separated by a narrow notch. Inner orbital angles obtuse and very slightly pro- 
duced. The orbital border bears three small tubercles — one superior, one external, the other inferior. 
Basal article of antenna very wide, much expanded outwardly, forming a part of floor of orbit; its 
antero-external angle is tuberculiform and scarcely more advanced than superior inner orbital angle. 
Posterior two-thirds of the carapace nodose; branchial regions crossed by oblique sulci, the inter- 
vening elevations being broken up into irregular lobulations. Antero-lateral margins cut into four 
rounded lobes, which in the young are more or less pointed. Carapace and chelipeds naked and 
shining. 
Chelipeds enlarged in the male; the arm has two spiniform tubercles in front; carpus smooth; 
hand compressed; dactylus as long as palm; fingers widely gaping, each provided with a large tooth, 
that is near the base in the dactylus, but in the middle of the gape in the pollex; in the female the 
fingers gape less and are without large teeth. Ambulatory legs somewhat spinous and covered with 
a brush-like coating of stout and slender setae. 
Color, sage green or bluish green, in alcohol. 
Dimensions of male: Length, 21.2 mm.; width, 24.2 mm. 
Bahamas; Florida Keys to Brazil, to a depth of 20 fathoms; abundant on coral reefs. Porto Rico: 
Boqueron Bay; Guanica Bay, on coral reef; Ponce reefs; Arroyo; Cabal lo Blanco Reef, Vieques; 
Ensenada Honda, Culebra; Fajardo; San Juan (G. M. Gray); Aguadilla (Gundlach). 
•Mithrax coryphe (Herbst) . 
Cancer coronatus Herbst, Natur. Krabben u. Krebse, x, 184, pi. xi, f. 63. 1785. (Not Cancer coronatus Molina, 1782.) 
Cancer coryphe Herbst, op. c.it., in, Heft 2, p. 8, 1801. 
Mithrax (Mithraculus) coronatus Miers, Jour. Linn. Soc. London, xiv, 667, 1879. 
Mithrax coryphe Rathbun, Ann. Inst. Jamaica, x, 11, 1897. 
Carapace much wider than in M. sculptus, about one-third wider than long; antero-lateral and 
postero-lateral margins forming a right angle; lobulated anteriorly as well as posteriorly, and more 
deeply than in M. sculptus. Front narrower than in M. sculptus; basal antennal joint much narrower. 
Margins of arm tubereulate; wrist uneven. Carapace and chelipeds naked except on the frontal lobes, 
but not shining. 
Dimensions of male: Length, 14 mm.; width, 19.4 mm. 
Bahamas; from Florida to Brazil to a depth of 30 fathoms. Porto Rico: Puerto Real; Boqueron 
Bay, on coral reef; reefs at Ponce; Arroyo; Ensenada Honda, Culebra. 
Genus MICROPHRYS Milne Edwards. 
Microphrys Milne Edwards, Ann. Sci. Nat. (3), xvi, 251, 1851. 
Carapace broadly subpyriform and somewhat depressed, with dorsal surface uneven and tuber- 
culated, with a small lateral epibranchial spine; preocular spine sometimes not developed. Orbits 
small, circular, with closed fissures. Spines of rostrum slender and more or less divergent. Abdomen 
seven- jointed. Eyes small. Basal antennal joint considerably dilated and armed with a long spine at 
antero-external angle, which is visible in a dorsal view; the movable joints and the flagella are not 
concealed by the rostral spines. Merus of outer maxillipeds distally truncated, the antero-external 
angle somewhat produced and rounded and the antero-internal angle emarginate. 
Chelipeds of moderate size, with the palm compressed and more or less enlarged; fingers of the 
male gaping. Ambulatory legs rather short, with arms and wrists sometimes armed with spines; 
dactyli slightly curved. 
Key to the Porto Rican species of the genus Microphrys. 
A. No Jateral laminiform processes on carapace. One branchial spine bicornutus 
A'. Two lateral laminiform processes, one hepatic, the other branchial. Two branchial spines platysoma 
