248 Memoirs of the Indian Museum [Vol. V, 



Family PORTUNIDAE. 



Genus SCYLLA, de Haan. 



Scylla serrata (Forskâl). 



1899. Scylla serrata, Alcock, Journ. Asiat. Soc. Bengal, IyXVIII, p. 27. 



This species is common in the Chilka Lake, in the outer channel and in the main 

 area, at all seasons of the year and is found both when the water is fresh and when 

 it is as salt as the Bay of Bengal in the vicinity. 



In young specimens , as Alcock has noted, the frontal lobes are indistinct and 

 there is an interrupted transverse granular line across the gastric region; the latter 

 is conspicuous even in specimens in which the carapace is 50 mm. in breadth. 



Scylla serrata is the common edible crab of India and is brought into the markets 

 in great numbers. It is abundant in estuaries, backwaters and mangrove swamps 

 and is evidently able to live in water without a trace of salinity. In the Chilka Lake 

 it must exist in fresh water for several months in the year and large specimens have 

 been taken in the Gangetic delta far beyond the reach of tidal influence. The cara- 

 pace of a male found under these conditions at Gatiaghar in the Hughli district is 

 135 mm. in breadth. The species, however, grows to a much greater size than this. 

 In a giant male in the Indian Museum the carapace is 147 mm. in length and 211 

 mm. in breadth, the length of the larger chela being 195 mm. This individual is, 

 I believe, the largest specimen known. 



Examples of the Cirripede, Dichelaspis cor, Aurivillius, are commonly found 

 attached to the branchiae of specimens found in the outer channel, but were never 

 obtained on individuals caught in the main area of the lake. 



Scylla serrata has a very wide Indo-pacific distribution extending from the Red 

 Sea and the eastern coasts of Africa to Japan, New Zealand and Oceania. It is ap- 

 parently not found at the Hawaiian Is. 



Genus NEPTUNUS, de Haan. 



1899. Neptunus, Alcock, Journ. Asiat. Soc. Bengal, LXVIII, p. 28. 

 1897. Portunus, Rathbun, Proc. Biol. Soc. Washington, II, p. 155. 

 1908. Lupa, Stebbing, Ann. S. African Mus., VI, p. 11. ' 



Those interested in the question of the suppression of this long established name 

 should consult the papers by Miss Rathbun and Stebbing cited above. 



Neptunus pelagicus (Linnaeus). 



1899. Neptunus pelagicus, Alcock, Journ. Asiat. Soc. Bengal, LXVIII, p 34. 

 This species is common in the Chilka Lake, both in the outer channel and in the 

 main area; like Scylla serrata it is used as an article of food. It is, apparently, un- 

 affected by alterations in salinity and is equally abundant at all seasons of the year. 



1 In this paper Stebbing supports the claims of Lupa against those advanced by Miss Rathbun for 

 Portunus. To these arguments Miss Rathbun has not, I believe, made any reply, yet continues to use 

 Portunus for the species so long known by the unequivocal Neptunus, de Haan. 



