<)60 DR- W. T. CALMAN ON A NEW [DeC. 15, 



'6. On a new River-Crab o£ the Grenus Gecarcinncus from 

 New Guinea. By W. T. Calman, D.Sc, F.Z.S., British 

 Museum (Natural History) . 



[Received November 8, 1908.] 



(Plate LXVIII.*) 



The genus Gecarcinucus was established in 1844 by H. Milne- 

 Edwards t for a species, G. jacquemontii, which occurs in various 

 localities in the neighbourhood of Bombay. Milne -Edwards 

 referred the genus to the family Gecarcinidae, and in this he was 

 followed by Dana J, Wood-Mason §, and Ortmann Ij. Alcock^, 

 however, has pointed out that, in spite of its great resemblance 

 to the Land-Crabs, the proper place of the genus is with the 

 River-Crabs (Potamonidse) and it is included by Miss Rathbun ** 

 in her monograph of the latter family. 



Sir "William Ingram, B.A., F.Z.8., has recently presented to the 

 Natural History Museum several specimens of a new Crab from 

 New Guinea which I refer to the same genus and in which the 

 Gecarcinoid facies is even more strongly marked than in the 

 Indian species. 



Gecarcinucus ingrami, sp. n. 



Carapace about three-fourths as long as broad, very deep, very 

 convex antero-posteriorly, less so from side to side. Cervical 

 groove strongly marked, its lateral limbs neArly longitudinal, 

 becoming obscure just before reaching the antero-lateral margin. 

 Cardiac region partly defined posteriorly. A transverse groove 

 behind each branchial region. Mesogastric groove short, deep, 

 not forked. Branchial regions strongly convex, the gastric and 

 cardiac less so. Epigastric lobes prominent and rounded, separated 

 from front by a transverse groove which runs behind the orbits ; 

 surface smooth, veiy faintly rugose near latei'al margins. 



Front generally a little less than one-fourth of width of cai^apace, 

 nearly vertically deflexed, its margin smooth. Seen from above its 

 outline is concave ; from in front, its lower edge is slightly convex 

 and its lateral margins convei^gent ; in the middle it is strongly bent 

 inwards, touching the epistome between the antennular fossse. 

 Orbits not entirely raised above lateral margin of carapace, roughly 

 quadrilateral, wider than high. Seen from in front, they are 

 inclined downwards and outwards, but are not produced at the 

 outer corner into a gutter-like sinus as in G. ja^queviontii. 



Outer orbital angle hardly dentiform as seen from above ; a 



* For explanation of the Plate see p. 963. 



t Vovage dans I'lnde, par V. Jacquemont, Zool. Crustaces, p. 4, pi. i., 18M. 

 X U.S. Expl. Exp., Crust, i. p. 375, 1852. 

 § Jour. Asiat. Soc. Bengal, xl. pt. 2, p. 190, 1871. 



!! Zool. Jahrb., Abth. Syst. vii. p. 732, 1894; Bronn's Thierreicli, Crust, p. 1178, 

 1899. 



^ Jour. Asiat. Soc. Bengal, Ixix. pt. 2, p. 279, 1900. 

 ** Nouv. Arch. Mus. Paris, (4) viii. p. 66, 1906. 



