i6o 



not observed to be transversely sulcate, and exhibits "a broad, shallow bight in the middle" 

 (no small, triangular notch), the hairy patch of the wrist is absent and the ambulatory legs are 

 comparatively more slender than usual, but these differences may be accounted for, perhaps, 

 by the very small size of the animal (length of carapace 5 mm.). 



'Sly a"' specimens have a maximum breadth of carapace of 9.75 and 8.5 mm. and a 

 length of 8 and 7 mm.; the Q, that has lost the chelipeds, is 12 mm. wide and 9.5 mm. long. 

 The abdomen of the latter sex exhibits nearly exactly the same, triangular shape as that ot 

 the d", but it is regularly tapering from the third segment to the terminal one, which latter is 

 elongate-triangular; the tips of the elongate and slender pleopods project in a bunch from 

 beyond the end of the abdomen. The first segment of the abdomen of the d' is unusually long 

 and gradually widens towards the next segment, which is as broad as the third. 



If mv list of synonyms be right, the species extends over the whole Indian Ocean : from 

 the Seychelles to the Mergui Archipelago, the Andamans, Suvadiva Atoll, INIadras, and to the 

 Gulf of Siam ; it occurs at Hongkong, in the Mokiccas, and at the coast of Australia (Port 

 Denison, Port Mollc), always in shallow waters of 20 — 40 fathoms depth. A subspecies (atlanticd) 

 has been described by Miers (1881) from Goree Island (Senegambia). 



PsopheticuS Wood-Mason. 



1890 — 91. Psopheticiis Wood-Mason. Admin. Rep. Mar. Survey of India, p. 20 (n o m e n n u d u m), 

 1899. Psopheticiis Alcock. "Investigator" Deep-Sea Brachyura, p. 72. 



As Alcock remarks the genus is nearly related to Carcitioplax\ indeed, it are the 

 chelipeds, and more particularly the quadrate wrist with its acute external tooth, that are 

 similar in both genera; as in Carciiioplax and Piltimnoplax the front is square-cut, overhanging 

 the antennulae; and, as in Pseudorhombila, the dactyli of the last pair of legs are styliform, 

 not depressed. The fronto-orbital breadth is usually nearly equal to the greatest width of 

 carapace ; the external orbital angle is strongly projecting, flattened, and at a considerable 

 distance behind it there is one acuminate epibranchial tooth. 



The three species show a distinct preference to the deeper parts of the ocean bottom, 

 occurring mostly beneath the 100 fathoms line. 



Key to the species : 



1 . Carapace subquadrate, width between external orbital angles 



about three-fourths the greatest breadth or nearly equal to it 2 

 Carapace subcircular, with the lateral margins strongly arched ; 

 distance between external orbital angles about two-thirds 

 the greatest breadth. Meropodites of walking legs with a 

 single subdistal spine. First segment of abdomen of cf entirely 

 covering the sternum and wider than second and third segment Ps. hughi Rathbun i) 



2. Distance between external orbital angles nearly equal to greatest 



i) Proc. U.S. Nat. Mus., v. 48, 1914, p. 144. Hab. Philippine waters (near Northern Mindanao), in depths of 200— 220 fathoms. 



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