256 



Memoirs of the Indian Museum. 



[Voi,. V, 



The largest of the two immature individuals is only 15 mm. in total length. 

 The eyestalks have the same form as in the adults, but are rather more convex dor- 

 sally and the patch of retinal pigment is proportionately much larger. The segments 

 of the antennal and antennular peduncles are of proportions similar to those of adults 

 and this is also true of the first legs, except that, in the larger of the two, the carpus 

 is rather longer in comparison with its breadth. None the less there is still a very 

 great difference in this respect between the right and left carpus of this pair. The 

 fingers of the large chela, which is little more thin 3 mm. in length, show only faint 

 indications of teeth and the surface of the entire limb is smooth and polished. The 

 telson is similar to that of the adult, but the sculpture is less defined. 



Callianassa maxima was described by A. Milne-Edwards from a single chela of 

 gigantic dimensions obtained in a sub-fossil condition in Siam, many miles from the 

 sea. This chela is 60 mm. in length, nearly three times the size of that of the indi- 

 vidual from Madras. The granulation as described and figured in the sub-fosssil chela 

 is much more pronounced than in any of the living examples obtained on the Indian 

 coast; but this, I believe, is largely a matter of age. The armature of the inner 

 margin of the dactylus is apparently very characteristic and in this respect there is 

 the closest possible resemblance between the Indian specimens and that from Siam. 



That this species, hitherto known only as a fossil, should now be discovered in 

 a living state need occasion no great surprise ; A. Milne-Edwards at the end of 

 his description remarks l IC Peut-être dècouvrira-t-on un jour que cette espèce vit encore 

 sur les côtes de Siam, car il est probable que les alluvions dans lesquelles elle a été 

 trouvée sont relativement peu anciennes et analogues à celles qui existent sur certains 

 rivages des mers de Chine et de l'océan Indien, ou on a rencontré à l'état fossile des 

 espèces de crustacés qui aujourd'hui vivent encore dans les mêmes mers, tels que la 

 Scylla serrata et YIxa canaliculata , à côté d'espèces inconnues aujourd'hui, telles que 

 le Macrophthalmus Latreillei. " Since this passage was written living examples of the 

 last named species have been found. 



Callianassa maxima is apparently allied to C. turnerana } White *, but the latter 

 species is readily distinguished by the armature of the merus and dactylus of the 

 larger chelipede, by the absence of surface granulation on this limb, by the much 

 shorter carpus of the smaller chelipede, by the trispinous rostrum and by the form 

 of the telson. C. turnerana, with which C. diademata , Ortmann, is apparently synony- 

 mous 3 , is found in the Cameroons in W. Africa, in the rivers of which it is sometimes 

 found in prodigious numbers. According to Vanhöffen + , the species is restricted to 

 brackish water and the swarms appear at intervals of approximately three years, a 

 period which he regards as that of the normal life-cycle. 



The history of the Madras specimen is unknown ; it probably came from one of 

 the backwaters in the vicinity of that city. Of the Chilka specimens, the solitary large 

 limb (which contains muscular tissue and is not merely a dessicated fragment) was 



1 loc. cit., p. 98. a White, Proc. Zool. Soc, London, 1861, p 42, pi. vi. 



6 I^enz, Sitz-ber. Ges. naiurf. Freunde, Berlin, 1911, p. 316. * Vanhöffen, ibid., 1911, p. 105. 



