196 BULLETIN 166, UNITED STATES NATIONAL MUSEUM 



Description. — Minute. Carapace orbiculate, flat, margin smooth, 

 slightly elevated. Rostrum with three small acute denticles. Sides 

 bidentate, tooth at middle strong, markedly acute. Abdomen large, 

 bent, orbiculate. Feet smooth, unguicidate. (Fabricius.) 



Color. — Dark, feet ferruginous. (Fabricius.) 



Range. — Known only from original specimen from Tierra del Fugeo. 



Family CALAPPIDAE Dana 



Calappidae and Matutidae Dana, United States Exploring Expedition, Crustacea, 



pt. 1, pp. 393, 394, 1852; pt. 2, p. 1427, 1853. 

 Calappidae Alcock, Journ. Asiatic See. Bengal, vol. 65, p. 137, 1896. 



The afterent channels to branchiae open behind pterygostomian 

 regions and in front of chelipeds. Antennae small. Outer maxilU- 

 peds 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 SUBFAMILIES AND AMERICAN GENERA OF THE FAMILY CALAPPIDAE 



A*. Last three joints of third maxillipeds not hidden by the mero- 

 podite. Orbits not separated from antennular sockets. 



CALAPPINAE (p. 197) 

 B*. Carapace provided behind with a pair of lateral clypeiform 

 expansions, under which the ambulatory legs may be 



concealed Calappa (p. 197) 



B^. Carapace without lateral clypeiform expansions. 



C. Carapace with a strong spine at middle of lateral mar- 

 gin. Outer maxillipeds do not meet across the mouth, 



thus exposing mandibles Mursia (p. 215) 



C^. Carapace narrow, without spine at middle of lateral 

 margin. 

 Di. Merus of cheliped with a very long, outstanding spine. 

 Stridulating ridges on inner surface of manus and 



suborbital region Acanthocarpus (p. 220) 



D^. Merus of cheliped without long spine. Carapace sub- 

 circular, a small spine at lateral angle Cycloes (p. 225) 



A'. Last three joints of third maxillipeds hidden by the meropodite. 

 Orbits more or less separated from the antennular sockets. 



MATUTINAE (p. 234) 

 B'. Carapace broad, suboval, convex, regularly arcuate in front. 



A well-marked depression below orbit Hepatus (p. 234) 



B^ Carapace more or less angular, surface uneven. A very 

 slight depression below orbit. 

 C Carapace subrectangular, broader than long; lateral re- 

 gions concave above Hepatella (p. 247) 



C^. Carapace narrow, octagonal. Front rostrate Osachila (p. 248) 



