|Abstract||The genus Pyxidognathus was established by A. Milne-Edwards (Bull.|
Soc. Philom. Paris, ser. 7, t. 3, 1878, p. 109) on a species, named by him P. granulosus, that was found in fresh or slightly brackish water in the island of Ovalau. A few months afterwards, in April 1879, de Man described a specimen under the name Hypsilograpsus deldeni nov. gen. nov. spec. (Notes Leyden Mus., v. 1, p. 72), collected by van Delden in 1836 near Manado (Celebes); this specimen, however, was recognized by de Man himself (Notes Leyden Mus., v. 5,1883, p. 159) as being probably identical with the species of Milne-Edwards, having had the opportunity of examining an original drawing of the animal, prepared by the French author.
Dr. de Man has, on my request, kindly sent me this drawing, and after a careful comparison between this and the original Hypsilograpsus specimen, I am fully convinced that the specimens of Milne-Edwards and of de Man belong really to the same species, and that the name Pyxidognathus therefore has priority.
In 1888 de Man made known another species of this genus, P. deïanira (Journ. Linn. Soc. London, v. 22, p. 148, pl. 10, f. 4—6), observed in mangrove-swamps of the Mergui Archipelago, and finally Alcock described a third species P. fluviatilis (Journ. As. Soc. Bengal, v. 69, prt 2, 1900, p. 408, Ill. Zool. „Investigator", Crust., prt 10, 1902, pl. 66, f. 3—3a), collected in fresh water in the Jessore District (British India).
The discovery of a new species, referable to this genus, in a collection belonging to the Amsterdam Zoological Museum, induced me to give an account of Pyxidognathus, the more readily because I could not only