310 Records of the Indian Museum. [Vol. XVI, 



The genera exhibit rather complex inter-relations. In the 

 form of the abdomen and in the possession of hairy-edged pouches 

 indicating openings into the branchial cavit3^ Scopimera is related 

 to Tympanomerus, while Dotilla and Dotillopsis agree in the deep 

 sculpture of the upper surface and side- walls of the carapace. On 

 the other hand Scopimera and Dotilla resemble each other and 

 differ wideh^ from Dotillopsis and Tympanomerus in the structure 

 of the ultimate segments of the second maxilliped. 



The genus Ilvoplax, which was described in 1858,' is based on 

 a single species, /. tenella, " found at Whampoa, China, along the 

 banks of the Canton River (brackish water), living in holes in the 

 mud, exposed at low water. ' ' The fact that the meral segments 

 of the legs possess tympana indicates that the genus must be referred 

 to the Scopimerinae. Stimpson compares it with M acrophthalmus 

 and remarks that it forms " a connecting link between the Macro- 

 phthalmidae and the Dotillidae." To my mind it is unquestionably 

 a very close ally of Tympanomerus and I strongly suspect that it 

 will prove to be synon^-mous with that genus. This, however, 

 cannot be accurately determined until /. tcnella has been re- 

 discovered. 



Genus Scopimera, de Haan. 



1833. Ocypode, subgen. Scopimera, de Haan, in Siebold's Faun. Japov., 



Crust., pp. 5, 24, 

 1852. Scopimera, Milne-F^dwards, Auii. Sci. nat.. Zoo/., (3) XVIII, 



P- 153- 

 1900. Scopimera, .'\lcock, 'Jourii. Asiaf. Soc. Bengal LXIX, p. 369. 

 1918. Scopimera, Tesch, Decap. Brachyiir. 'Siboga' Exped. bpp 4I' 45- 



The species may be distinguished by the following charac- 

 ters : — 



I. Ischium of third maxillipt-ds longer than merus. 



A. Mid-dorsal surface of carapace with large symmetri- 

 cal puckers or vesicles ; chela with strong carina near 

 inferior border ; last three segments of abdomen of 

 male racket-shaped, the 5th linear, \cry much nar- 

 rower than 6th or 7th ... ... ... S. crabricauda . 



B. Mid-dorsal surface of carapace not conspicuously puc- 

 kered ; chela with inferior border rounded ; 5th seg- 

 ment of abdomen of male not linear, little if at all 

 narrower than 6th and 7th. 



1. Tympana on meral segments of walking legs not 



divided b}' a ridge. 



a. Lateral border of carapace defined by a crest 

 throughout its length ; upper surface strongly 

 granular; chelipeds of adult male little more 



than twice length of carapace ... . S.globosa. 



b. Lateral border of carapace defined by a crest 

 only in its anterior half ; upper surface feebly 

 granular; chelipeds of adult male usually quite 



three times length of carapace. ... . . S. pilula. 



2. Tympana on meral segments of walking legs 

 (except for that on upper surface of last leg) 

 divided longitudinally by a narrow ridge. 



1 Stimpson, Proc. Acad. Nat. Sci. Pliiladelpliia X. p. 98(1858) and Smithson. 

 Misc. Coll. XI.IX, p. 100 (1907). 



