406 A. Alcock — Oarcinnlogical Fanna of India. [No. 3, 



94. Ptychognathns barhata (A. M. Edw.). 



Gnathograpsus barbatus, A. Milne Edwards, Nouv. Archiv. du Mus. IX. 1873, p. 

 316, pi. xvii. fig. 4. 



Ptychognathus barbatus, Ortmann, Zool, Jahrb. Syst. VII, 1893-94, p. 712 : 

 de Man, Zool. Jahrb., Syst., IX. 1895, p. 105. 



Carapace decidedly broader than long, flat, depressed, the regions 

 indistinct: the two postfrontal tubercles are fairly distinct, but there 

 is no distinct raised line on the posterior part of the epibranchial re- 

 gions, running obliquely parallel with the posterior borders, such as is 

 present in all the other Indian species. There is a good deal of tomen- 

 tum on the sides of the carapace. 



Front decidedly sinuous, not prominent, its extent is a little more 

 than two-fifths the greatest breadth of the carapace. 



The autero-lateral borders of the carapace are cut into 3 not very 

 conspicuous teeth (including the outer orbital angle) of which the 

 first is much the largest and the third much the smallest, as usual. 



Upper border of the orbit little sinuous: the antennules fold nearly 

 transversely. Anterior border of the buccal cavern finely granular. 



The exognath is elliptical, with a slightly convex surface : in the 

 male its greatest breadth is more than that of the ischiognath, in the 

 female it is slightly narrower than in the male. 



Chelipeds in the male about If times the length of the carapace, 

 the inner angle of the wrist little pronounced ; the hand massive, with 

 a tuft of hair in the finger-cleft and running some little distance along 

 the outer surface of both fingers ; the fingers are rather blunt, the dac- 

 tylus, which is about twice the length of the upper border of the palm 

 is longer slenderer and less strongly toothed than the fixed finger, 

 against which it closes rather obliquely. In the female the chelipeds are 

 about as long as the carapace and are not very massive, the inner angle 

 of the wrist is dentiform, there is no hair on the hand or fingers, and 

 the outer surface of the hand and fixed finger is traversed near the 

 lower border by a raised line. 



The leg-joints are less expanded and less abundantly plumed than 

 in the other Indian species, and there is no subterminal spine on the 

 anterior border of the meropodites. The 2nd aud 3rd pairs of legs are 

 about If times, the 1st pair about 1J times, and the last pair a little 

 over once, the length of the carapace. 



In the Indian Museum are 3 specimens from Diamond Island off 

 the Pegu coast and from Akyab, (besides numerous specimens from 

 Samoa). The carapace of an apparently adult male is 11 millim. long 

 and 14 millim. broad. 



