1896.] A. Alcock — Carcinological Fauna of India. 285 



The chelipeds of the adult male are unknown : in the female they 

 are not so stout as the first two pairs of legs. 



The second pair of legs in the female (adult male unknown) exceed 

 the first almost bj the length of the dactylus, they are three times 

 the length of the carapace and about 2| times the length of the 4th pair. 



The extreme length of the carapace of the largest specimen, which 

 is not adult, is 9'5 millim., the exti'eme breadth 9 millim. 



Andaman Sea 188 to 220 fms., and 238 to 290 fms. 



This species may possibly be only a variety of Ethusa orie7italis, 

 Miers, Challenger Brachyura, p. 330, pi. xxviii. fig. 4. 



305. Ethusa (Ethusina) investigatoris, n. sp. 



Carapace manifestly longer than broad, somewhat convex, smooth 

 to the naked eye though finely granular under the lens. 



The branchial regions are a good deal swollen both dorsally and 

 laterally, bulging out the lateral margins and making the carapace 

 a third broader across the middle of the branchial regions than across 

 the bases of the external orbital spines. 



The cardiac-intestinal region is well-defined and tumid, but nob 

 sunk below the level of the branchial convexities : the anterior regions 

 of the carapace are fairly well defined. 



The frontal portion of the carapace is separated from the rest of the 

 carapace by a transverse groove or crease. The external orbital spine 

 is long and needle-like, but its tip falls considerably short of the tips of 

 the rather long acute frontal spines. 



The basal antennal joint is huge and swollen, almost globular in 

 shape. Owing to its size the eyes are pushed outwards until the eye- 

 stalks have come to lie almost in the transverse axis of the carapace, 

 with the tips of the eyes just visible, dorsally, beyond the lateral edge 

 of the external orbital spine ; and in this position they are almost 

 immovably fixed. 



The chelipeds in the apparently adult male are symmetrical and 

 are not much stouter, except as to the hands, than the first two pairs 

 of legs ; the hands, however, are somewhat enlarged. 



The second pair of true legs exceeds the first by about a third of 

 the length of the dactylus ; they are more than three times the length 

 of the carapace, and about 2| times the length of the 4th pair. 



The abdomen of the male consists of 5 pieces, the 3rd-5th terga 

 being fused together. 



Length of carapace of an adult male 12*3 millim., extreme breadth 

 11*3 millim. 



Colours in life milk-white with the tip of the legs faint pink. 



