192 BULLETIN 12&^ UNITED STATES NATIONAL MUSEUM 



Ambulatory legs very slender, rather long, dactyli very delicate^ 

 (A. Milne Edwards.) 



Abdomen of adult female wide, swollen, and formed of four (not 

 three) articles, the fourth to seventh segments, inclusive, being 

 coalesced. 



Contains only one species. 



ESOPUS CRASSUS A. Milne Edwards 



Plate 222, figs. 10-12 



Esopus crassus A. Milne Edwards, Crust. R4g. Mex., 1875, p. 90, pi. 17. 

 figs. 1-lc (type-locality, off Barbados, 100 fathoms; holotype, Cat. No. 

 1944, M. C. Z.). 



Diagnosis. — Carapace oval, lobulate, finely granulate. Ambula- 

 tory legs smooth and slender. 



Description. — Carapace narrow, oval, and slightly narrowed in 

 front; entirely covered, excepting in the interlobular depressions, 

 with shining and almost confluent granules. Anterior part very 

 swollen. Interorbital space divided into three nearly equal lobes 

 by two longitudinal depressions which are connected behind with the 

 cervical suture. Protogastric lobes clearly marked on their outer 

 side; on the inner side they are confluent with the mesogastric lobe 

 which is elevated in a point above them; metagastric lobes confluent 

 on the median line and separated by a deep suture from the uro- 

 gastric lobes which are themselves confluent. Anterior cardiac lobe 

 conical, prominent, and surmounted by a large tubercle; posterior 

 cardiac, or intestinal, lobe much more depressed, and divided into 

 two portions by a transverse suture. Hepatic region small and 

 rounded. The branchial region bears on its middle portion a tubercle 

 smaller than that of the cardiac lobe; borders of metabranchial lobe 

 cut above the base of the legs into three blunt points. Pterygosto- 

 mian regions papillated and granulated. Basal article of antennae 

 covered with granulations similar to those of the front. Some large 

 granules on front of epistome. Abdomen also granulate. Chelipeds 

 of female cylindrical and very slender. Ambulatory legs smooth; 

 first three pairs nearly the same length; fifth a little shorter. (A. 

 Milne Edwards.) 



The median lobule of the front or interorbital space is divided 

 transversely in two, forming a short, buttonlike, rostral projection. 

 The anterior point of the mesogastric region is a smooth, white, oval 

 elevation. 



Measurements. — Female, holotype, length of carapace 13, width 

 8.4 mm. 



Range. — Known only from the unique type. 



Material examined. — Off Sandy Bay, Barbados; 100 fathoms; 

 December 29-30, 1871; Hassler Expedition; 1 female, holotype 

 (1944, M. C. Z.). 



