542 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. no. 



half. Ambulatory legs cylindrical, pubescent, the first pair one- 

 fourth longer than cheliped. 



Relationship. — Closely related to S. carbunculus Eathbun^ from 

 the Hawaiian Islands; in carhunculus, however, there are nine sub- 

 equal prominences on the hinder part of the carapace, the intestinal 

 and posterior branchial nodules being as large as the others; the 

 hepatic nodule is fused with the postocular, while in nodosus these 

 nodules are separate and very unequal in thickness. 



HYASTENUS TRISPINOSUS, new species. 



Type-locality. — Tawi Tawi Group, Sulu Archipelago: Tinakta 

 Island (N.), N. 82° W., 1.4 miles; lat. 5° 11' 50" N.; long. 119° 54' 

 E.; 10 fathoms; co. S.; Feb. 21, 1908; station 5159, Albatross. 



Holotype.— Male. Cat. No. 48213, U.S.N.M. 



Measurements. — Length on median line without spine, 10.9 ; length 

 of rostral horns, 5.4 ; width without spines, 7.8 ; width with spines, 9.7. 



A subtriangular carapace with three spines, one of which is median 

 just above the posterior margin, nearly erect, curved, acute, the other 

 two at the branchial angles, longer, slenderer, directed outward and 

 strongly upward, curved, with tip hooked forward. A low median 

 tubercle on the gastric and on the cardiac region; a large gastric 

 tubercle near the orbital sinus, and in the same horizontal line a very 

 small one, nearer the middle. A branchial tubercle on the lobe in the 

 angle between cardiac and intestinal regions; another much farther 

 forward near the margin. Three very large pterygostomian tubercles 

 besides the one formed by the projecting angle of the buccal cavity. 

 Rostral horns slender, moderately divergent, horizontal, acuminate. 

 Preorbital lobe with a Avell-developed anterior tooth; in front of it 

 shows the narrow spine of the antennal segment. Orbital sinus very 

 small and rounded ; outside it, the anterior margin of the postocular 

 cup is concave. The basal antennal segment bears on its outer margin 

 beside the distal spine, a large lobe at the middle, and far back a 

 small tubercle. 



Chelipeds slender, as long as carapace and one-third the rostrum ; 

 the specimen is j)erhaps not fully mature. Manus not enlarged; 

 fingers with a very narrow gape at base. The more distal spines of 

 the dactyli of the ambulatory legs are of good size. 



Relationships. — Near //. dlaeanthus (de Ilaan)- and II. spinosus 

 A. Milne Edwards;^ the median gastric tubercle in trispinosus is 

 farther forward than in diacanthus and occupies the position of the 

 anterior of the two spines in sjnnosus; but the most striking differ- 



1 Bull. U. S. Fish Comm. for 1903, pt. 3, 1906, p. 879, pi. 14, fig. 6. 



"Pisa {yaxia) diacaniha de Ilaan, Fauna Japon., Crust., 18:58, pi. 24, fig. 1 ; 1839, pi. 96 

 and pi. G. 



3 Nouv. Arch. Mus. Hist, Nat., I'aris, vol. 8, 1872, p. 2.^.0. 



