84 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
Tribe OXYSTOMATA or LEUCOSOIDEA. 
Carapace with antero-lateral margins arcuate or orbiculate; sometimes subglobose or more or less 
oblong, with subparallel margins. Epistome much reduced. Buccal frame more or less triangular, 
produced and narrowed forward, with margins anteriorly convergent. Six to nine pairs of branchiae. 
. Efferent channels opening at middle of endostome, which is produced forward. Afferent channels 
open either behind pterygostomian regions and in front of chelipeds, or at antero-lateral angles of 
palate. First antennae folded longitudinally or obliquely. The genital organs of the male are exserted 
either from the bases of the fifth pair of legs or from surface of sternal plastron. 
Family CALAPPIDAi Milne Edwards, 1837; De Haan, 1837; White, 1847. 
The afferent channels to branchiae open behind pterygostomian regions and in front of chelipeds. 
Antennae small. Outer maxillipeds not completely closing the buccal cavern and with the palpus not 
concealed by merus joint. Verges of male exserted from bases of fifth pair of legs. 
Key to the Porto Rican genera of the family Calappidie. 
A. Carapace with a posterolateral shield-like expansion or series of broad serrations, forming a vault beneath 
which the four ambulatory legs can be completely or largely concealed in flexion. Basal joint 
of antennse much dilated Calappa 
A'. Carapace without any trace of a postero-lateral shield-like expansion. Basal joint of antennse slender Cycloes 
Genus CALAPPA Fabricins 
Calappa Fabricius, Entom. Sys., Suppl., 309, 1798. 
Carapace strongly convex, rounded in front, much broadened behind by a pair of clypeiform 
expansions or wings, beneath which the ambulatory legs are concealed in flexion. Front small, some- 
what triangular, projecting usually little or not at all beyond level of orbits, bilobed. Orbits small, 
circular; eye-stalks short and thick. Antennulse nearly vertical. Basal joint of antennse very broad 
and filling a wide hiatus at inner angle of orbit. Outer maxillipeds not meeting, but leaving exposed 
mandibles and, in front of them, lamellar processes from first pair of maxillipeds. These processes 
form the bases of two channels separated by a deep vertical septum extending to antennulary fossae. 
Chelipeds very large, and in flexion fitting closely the front half of carapace, forming a sort of buckler. 
The merus has externally and near its distal end a transverse wing-like expansion. Hand strongly 
compressed, its upper border forming a high dentate crest. Chelipeds equal except for the fingers, 
which on one hand have outside near the base a stout projecting lobule. Abdomen in adult with the 
third, fourth, and fifth segments fused. 
Key to the Porto Rican species of the genus Calappa. 
A. Posterior margin of carapace with only broad and shallow teeth. 
B. No deep hollow between gastric and hepatic regions . flammea 
B'. A deep hollow between gastric and hepatic regions gallus 
A'. Posterior margin of carapace with a pair of spines near the middle sulcata 
Calappa flammea (Herbst). Plate 2. 
Cancer flammea Herbst, Natur. Krabben u. Krebse, ii, 161, pi. XL, f. 2, 1794; in, pt. 3, p. 19, 1803. 
Calappa flammea Bose, Hist. Nat. Crust., I, 185, 1802; Miers, Challenger Rept., xvii, 284, pi. xxm, f. 1, 1886. 
Calappa mamnorata Latreille, Hist. Nat. Crust., v, 392, 1803. (Not C. marmorata Fabricius.) 
Extreme length of carapace about two-thirds extreme breadth. Carapace, outer surface of wing- 
like expansion of the arm, upper surface of wrist, and outer surface of palm covered with coarse 
granules, more closely placed on anterior than on posterior half of carapace, and forming several 
longitudinal rows of flattened tubercles. Antero-lateral border crenulate and granulate; posterior border, 
exclusive of the wings, subentire with beaded edge. Wings well developed, with seven strong teeth with 
beaded edges, three behind and three in front of postero-lateral tooth. Pterygostomian regions thickly 
covered with hair. Front with a large notch, projecting little beyond orbits. Endostomial septum 
extends forward in a strong tooth not reaching level of front. The wing-like expansion at end of arm 
is conspicuously four-lobed; the crest of palm is eight or nine-toothed; its outer face has several large 
tubercles and a laminate inferior proximal spine. 
Dimensions of female: Extreme length, 80 mm.; width at sinus just in front of wings, 105 mm.; 
greatest width of carapace, 118 mm. 
North Carolina to Sabanilla, United States of Colombia, and Venezuela; Gulf of Mexico; Bermudas; 
Cape of Good Hope; probably Indian Ocean. Porto Rico: San Juan Harbor; Mayaguez; Boqueron 
Bay; Arroyo; Fajardo; Ensenada Honda, Culebra; Mayaguez (Gtmdlach). 
