1900.] A. Alcock — Car etiological Fauna of India. 371 



the middle line, the 5th is long linear and grooved, the 6th and 7th, 

 though separate, together form a racket-head. 



In the female the abdomen is of normal shape. 



In the Indian Museum are a male and female from Karachi. The 

 carapace of the male is 65 millim. long and barely 10 millim. broad. 



Tympanomerus, de Man, Rathbun. 



Dioxippe, de Man, Journ. Linn. Soc, Zool., XXII. 1887-88, p. 137 (1888) : nom. 

 prxocc. 



Tympanomerus, Rathbun, Proo. Biol. Soc, Washington, XI. 1897, p. 164. 



Carapace deep, quadrilateral, broader than long, the regions not 

 denned. Front narrow, deflexed : the orbits are trenches occupying the 

 whole anterior border of the carapace between the front and the antero- 

 lateral angles. 



Eyes, antennules, antennae and epistome as in Dotilla. Buccal 

 cavern large, a little narrowed and rounded anteriorly : the external 

 maxillipeds completely close the buccal cavern, the anterior outer corner 

 of the ischium is marked off as a distinct facet as in Dotilla and 

 Scopimera, the merus is much larger than the ischium, the palp arises 

 near the antero-external angle of the merus, and the exognath is small 

 and linear. 



Chelipeds in both sexes stouter, and in the male longer, than the 

 legs : fingers a little deflexed. 



Legs rather compressed, the two middle pairs a little longer than 

 the first and last pair: there are ill-defined tympana on the meropodites. 



The abdomen in both sexes consists of separate segments, and in 

 the male is narrow. 



Distribution : Japanese and Andaman Seas. 



The name Tympanomerus is a most unfortunate one, since the " tympana," 

 compared with those of Dotilla and Scopimera, are ill-defined and inconspicuous. 



66. Tympanomerus orientalis (de Man). 



Dioxippe orientals, de Man, Journ. Linn. Soc. Zool. XXII. 1887-88, p. 138, 

 pi. ix. figs. 8-10. 



Carapace square-cut, the length about four-fifths of the greatest 

 breadth, dorsally nearly flat with the lateral borders well defined 

 especially anteriorly, the surface a little lumpy in places : a perfectly 

 straight fine transverse ridge runs close to and. parallel with the 

 posterior border. 



Front grooved dorsally, hardly a fourth the breadth of the 

 carapace. The outer angle of the lower border of the orbit forms a 



