1895v] A. Alcock — Carcinological Fauna of India. 251 



zontal portion of the carapace, and the length of the 2nd joint is less 

 than one-third the breadth of the rostrum at its own point of origin — 

 the joint also being somewhat broadened. 



The chelipeds also vary. In certain males, both adult and young 

 (var. mascarenica partim), they are stouter than the other legs, are 

 very variably granular, are a little longer than the carapace, have the 

 hand very variably broadened and inflated, and the fingers closely 

 apposable only at tip. In all females they are a 



little shorter than the carapace, are quite smooth, are rather slenderer 

 than the other legs, and have slender palms, and fingers that are closely 

 apposable in the greater part of their extent. In 



certain other adult males they are intermediate in condition, approach- 

 ing more to the female type. 



The ambulatory legs are moderately stout and are hairy : the 1st 

 pair, which are the longest, are rather longer than the chelipeds ; the 

 others decrease gradually in length. 



Miers' valuable paper, Ann. Mag. Nat. Hist., 1885, Vol. XV. pp. 

 6-8 should be consulted. After examining over forty specimens from 

 the Andamans I adhere to Kossmann's synonomy and opinion (loc. cit.) 



The characters upon which the separation of M. mascarenica from 

 M. philyra is based are all variable ; and I think that we have here to 

 deal with a case of male dimorphism, such as is known to occur in 

 certain Beetles, where one form of male is abei'rant from the female 

 type while another form of male resembles the female in certain par- 

 ticulars : vide Bateson and Brindley, Variation in Secondary Sexual 

 Characters, P.Z.S., 1892, p. 585. 



Micippa thalia, Rerbst. 



Cancer thalia, Herbst, Krabben, III. iii. 50, tab. lviii. fig. 3. 



Micippa thalia, Gerstacker, Archiv. fur Naturgesch , XXII. 1856, p. 109 ; and 

 Adams and White, ' Samarang' Crust., p. 15; and A. Milne-Edwards, Nouv. Archiv. 

 du Mus., VIII. 1872, p. 238, pi. xi. fig. 1 ; and Kossmann, Eeise Eoth. Meer., Crust , 

 p. 8 (et varr.); and Miers, Zoology H. M. S. 'Alert,' pp. 182 & 198, and Ann. Mag. 

 Nat. Hist., 1885, Vol. XV. p. 10 (ubi synon.), and 'Challenger' Brachyura, p. 70 ; 

 and [Cano., Boll. Soc. Nat., Napol., III. 1889, p. 179] ; and Ortmann, Zool. Jahrb. Syst., 

 etc., VII. 1893, p. 60; and Henderson, Trans. Linn. Soc, Zool., 1893, p. 348. 



Micippa thalia (=var. aculeata), de Haan, Faun. Japon. Crust., p. 98, pi. xxiii. 

 fig. 3; andKrauss, Siidafr. Crust., p. 51 ; andBianconi, Mem. Ac, Bologna, III., 1851, 

 p. 103, pi. x. fig. 2 ; and Kossmann, Reise Roth. Meer., Crust., pp. 5 and 8, pi. iii. 

 fig. 5 ; and Hilgendorf, MB. Akad., Berl., 1878, p. 786 ; and Richters, Mobius, Meeres- 

 fauna, Maurit., p. 142; and Miers, Ann. Mag. Nat. Hist., 1885, Vol. XV. p. 11 (ubi 

 eynon.); and De Man, Journ. Linn. Soc, Zool., Vol. XXII. 1888, p. 20; and Mary 

 J. Rathbun, Proc U. S. Nat. Mus., Vol. XVI. 1893, p. 92. 



J. ii. 32 



