Crustacea Decapoda and vStomatopoda. 233 



Genus Pyxidognathus, A. Milne-Edwards. 

 Pyxidognathus dcianira, de Man. 



1888. Pyxidognathus deianira, de Man, Journ. Linn. Soc. Zoo!., XXII, p. 148, pi. x, figs. 4-6. 



Dr. Annandale obtained a single specimen of this scarce species among the roots 

 of a dead palm trunk in the Patani River, below the town of Patani in the Siamese 

 Malay States. The individual is a male with carapace 9 mm. in breadth. Except 

 for the slightly more acute teeth on the antero-lateral margin of the carapace, the 

 specimen bears the closest resemblance to two smaller males, co- types of the species, 

 that are preserved in the Indian Museum. 



The species has hitherto been recorded only from Mergui, where it was obtained 

 in mangrove swamps. 



Subfamily SESARMINAE. 



Genus Sesarma, Say. 

 Sesarma quadratum (Fabricius). 



1887. Sesarma quadrata, de Man, Zool. Jahrb., Syst., II, p. 683, pi. xvii, fig. 2. 

 1890. Sesarma, quadrata, de Man, Notes Leyden Mus., XII, p. 99. 



1892. Sesarma quadrata, de Man, in Weber's Zool. Ergebn. Reise Niederl. Ost-Ind., II, p. 328. 



1895. Sesarma (Parasesarma) quadrata, de Man, Zool. Jahrh., Syst., IX, p. 182. 



191 7. Sesarma {Parasesarma) plicata, Tesch, Zool. Meded. Mus. Leiden, III, p. 187 [syn.). 



Several specimens were found at different places in the outer lake of the Tale Sap 

 (Kaw Keoh, Kaw Deng, Koh Yaw and Singgora) ; they were for the most part found 

 under stones or running on the shore at some distance from the water. All appear 

 to belong to the true 5. quadratum as redefined by de Man. 



Sesarma haswelli, de Man. 



1888. Sesarma haswelli, de Man, Journ. Linn. Soc, XXII, p. 175. 



1917. Sesarma {Chiromantes) haswelli, Tesch, Zool. Meded. Mus. Leiden, III, p. 158. 



A single example of this species, an ovigerous female 16 mm. in breadth, was ob- 

 tained by Dr. Annandale near Singgora. 



Alcock ' included S. haswelli, along with S. lividvim, A. Milne-Edwards, and 5. 

 dussumieri, Milne- Edwards, in his synonymy of 5. hidens (de Haan), being- evidently of 

 the opinion that the five forms distinguished by de Man in 1888 in his " section C" 

 (loc. cit., p. 175) were only based on individual variations of a single wide-spread 

 species. De Man in 1902 ^ dissented from Alcock' s opinion. 



In. the Indian Museum are preserved the type of 5. haswelli, other specimens from 

 Mergui originally determined by de Man as S. livida, a large number of examples 

 examined by Alcock and several additional samples obtained in recent years. 



On examining this material I find little difficulty in separating it into groups, 

 corresponding to those that de Man and Tesch recognize as distinct species. I have 

 no doubt that Alcock formed a wrong estimate of the variability of the forms in- 

 cluded in the hidens-gxow^ and that it will be necessary to subject the Indian rnaterial 

 to a thorough revision. 



1 Alcock, Journ. Asiat. Soc. Bengal, I/XIX, p. 415. 



2 De Man, Abhandl. Senck. naiurf. Ges., Frankfurt, XXV, p. 538 (1902). 



