354 



BULLETIN 129, UNITED STATES NATIONAL MUSEUM 



armed with an oblique keel immediately behind the next joint; fol- 

 lowing joints slender. Outer maxillipcds small; merus joints distally 

 truncate, antero-external angle obtuse, antero-internal angle emar- 

 ginate. 



Chelipeds moderately elongate, rather slender; palms slightly 

 compressed and more than twice as long as broad; fingers with an 

 intermarginal hiatus at base. Ambulatory legs very slender and of 

 moderate length, joints subcylindrical, unarmed; dactyli slightly- 

 arcuate. 



Contains only one species. 



PICROCEROroES TUBULARIS Miers 



Plate 126; plate 254, figs. 2-5 

 Picroceroides tubularis Miers, Challenger Rept., Zool., vol. 17, 1886, p. 77, 

 pi. 10, figs. 1-lc (type-localities, Fernando Noronha and Bahia, in 

 shallow water; types in British Mus.). — Rathbun, Bull. U. S. Fish 

 Coram., vol. 20, for 1900, pt. 2, 1901, p 76. 



Diagnosis. — -Orbits tubular. Rostral and preocular horns very 

 long and slender. Ambulatory legs slender. Abdomen and sternum 

 deeply furrowed. 



Description. — Carapace moderately convex, much longer than 

 broad, but little dilated at branchial regions. Frontal space con- 

 cave; gastric region somewhat elevated and 

 obscurely tuberculated; the cardiac region 

 bears a rounded prominence and the intes- 

 tinal region a slender spine; the cervical and 

 branchio-cardiac sutures are continuous and 

 form a longitudinal sinus, separating the 

 branchial from gastric and cardiac regions. 

 The tubular orbits project laterally to a 

 remarkable degree, and each bears a very 

 long preocular and a small postocular spine, 

 and has two notches in the inferior and one 

 in superior margin. Rostral spines in adult 

 male four-fifths the length of remainder of 

 carapace; very slender, slightW curved, and 

 remote from each other at base. The basal 

 antennal joint has, besides the antero-internal crest, two small teeth 

 on margin of orbit and a third on distal margin. 



Chelipeds unevenly granulated; the outer surface of palm has a 

 slight longitudinal depression near upper surface; the dactylus has 

 a strong tubercle near its base. Carapace and ambulatory legs 

 rather thinly pubescent; the margins of rostrum and of the free 

 peduncular joints of antennae have some longer hairs, some of which 

 are clavate. 



Measurements. — Male (24082), median length of carapace, from 

 posterior to anterior margin, 22.5; length of horn 19; width of 



Fig. 115.— Picroceroides tubu- 

 laris (24082), MAXILLIPED, X 8.58 



