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Chelipeds and 2nd— 4th legs rugose, the rugcie of the carpi and propodi 

 being fringed with short bristles and with dark-coloured corneous granules 

 and denticles : on the fingers of the chelipeds and 4th pair of legs, and on 

 the stout dactyli of the 2nd and 3rd pair of legs, the black corneous tuber- 

 cles are very numerous and are often spiniform or squamiform. 



Usually the legs of the two sides are symmetrical, those of the 2nd pair 

 being the longest and exceeding those of the 3rd pair by the dactylus and 

 the larger cheliped by about half the dactylus ; but sometimes in the female 

 the 2nd left leg is shortened and the 3rd right leg lengthened. The coxje of 

 the 5th legs are not produced to any special extent. 



Colours of fresh spirit specimens : exposed dorsal surface of body and 

 appendages rich tortoise-shell, ventral surface bluish-purple. In old spirit 

 specimens the colours fade a good deal. 



The adult male is much larger than the female. In the largest male of 

 the Museum collection the carapace measures 187 millim. (about 7% inches) 

 in extreme length and the same across the branchial regions. 



Geographical distribution : from the Comoro Islands (off the coast of 

 Mozambique), Madagascar, Keunion, Mauritius, Seychelles and Chagos Is. 

 (Diego Garcia), to the Andamans (S. Sentinel I.) and Nicobars, then through 

 the East Indian Archipelago to the Liu Kiu Is., and through Polynesia to 

 the Paumatu Archipelago, Fanning, and Sandwich Is, 



Within the limits of British India Birons latro is known to occur only in 

 the Nicobars, and at S. Sentinel I., a western outlier of the Andaman group. 

 In 1889 it was very abundant at S. Sentinel, where the officers of the 

 "Investigator" observed it crouching under fallen trunks and between the 

 buttress-roots of large trees during the heat of the day, but becoming active 

 at times of cloud and rain, and towards nightfall Individuals carried 

 away captive were noticed to be nocturnal and cannabalistic, and one was 

 seen deliberately drinking rainwater. The creature though powerful is sluggish 

 and unaggressive, and uses its long 2nd pair of legs rather than its nippers 

 in offence. 



