1899.] A. Alcock — Carcinological Fauna of India. 61 



lower border, though not prominently dentiform, is acuminate, and the 

 lobule at the outer end of this border is sharply dentiform. 



There is a prominent tooth on the lobule at the outer angle of the basal 

 antennal joint : this is present in no other Indian species. 



Chelipeds about 2J times the length of the carapace (in the male) : 

 all three surfaces of the arm and almost all parts of the surface of the 

 hand are covered with granular squamiform markings. Arm with 3 

 enlarged spines on the anterior border, the posterior unarmed. Wrist 

 costate on the upper and outer surface ; the inner angle spiniform ; 

 only two spinules at the outer angle. Hands (in adults only) more than 

 usually unequal for a Goniosoma : in one cheliped (adult) the palm is 

 swollen and markedly longer than the fingers, in the other it is not 

 swollen and is not much longer than the fingers : the hand is 7-costate 

 and there are 4 spines on its upper surface. 



The merus of the last pair of legs is about four-fifths as broad as 

 long and has a spine near the distal end of its posterior border, the 

 propodite has one or two inconspicuous spinules near the far end of its 

 posterior border. 



In both sexes the 2nd and 3rd abdominal terga are transversely 

 keeled : in the male the 6th tergum is a good deal broader than long 

 and has strongly curved sides. 



In the Indian Museum are 43 specimens from the Madras coast and 

 the Persian Gulf, besides one from Nagasaki and one from Hongkong. 



37. Cliarybdis (Goniosoma) natator (Herbst) A. M. Edw. 



Cancer natator, Herbst, Krabben. II. v. 156, pi. xl. fig. 1. 



Portunus sanguinolentus, Bosc, Hiat. Nat. Crust. I. p. 218. 



Thalamita natator, Milne Edwards, Hist. Nat. Crust. I. 463, pi. xvii. figs. 13, 14. 



Charyhdis natator, De Haan, Faun. Japon. Crust, p. 10. 



Charyhdis granulatus, De Haan, Faun. Japon. Crust, p. 42, pi. i. fig. 1 : Krauss, 

 Sudafr. Crust, p. 24 : Stimpson, Proc. Ac, Nat. Sci. Philad. 1858, p. 39. 



Goniosoma natator, A. Milne Edwards, Archiv. du Mus. X. 18(51, pp. 370, 385 : 

 Hilgendorf, MB. Ak. Berl. 1878, p. 801 : Miers, Zool. H. M. S. Alert, pp. 518, 539 : 

 F. MuUer, Yerh. Ges. Nat. Basel, VIII. 1886, p. 475: de Man, Archiv. f. Naturges. 

 LIIl. 1887, i. p. 334, pi. xiii. fig. 5, and in Weber's Zool. Ergebn. Niederl. Ost.-Ind. 

 II. 1892, p. 285 : Walker, Journ. Linn. Soc. Zool. XX. p. 110 : J. R. Henderson, 

 Trans. Linn. Soc, Zool., (2) V. 1893, p. 374. 



Length of carapace about five-sevenths the breadth. 



Carapace slightly convex, with a somewhat mangy pile, crossed 

 transversely by several rather coarse granular more or less broken 

 ridges : the most conspicuous of these ridges runs — broken only by tlie 

 cervical groove — right across between the last teeth of the antero-lateral 

 borders, and in front of this are two — the anterior one widely divided 

 in the middle — on the gastric region, while behind it are two short ones 



