378 A. Alcock — Carcinological Fauna of India. [No. 3, 



elegantly denticulate, the lower border unevenly crenulate. Eyestalks 

 slender and curved: the eye does not reach to the end of the orbital 

 trench. 



When their flagella are folded the external maxillipeds completely 

 occlude the buccal cavern : the suture between the ischium and merus 

 is hardly at all oblique. 



In the adult male the chelipeds are from 2| to 3 times the length 

 of the carapace and longer than any of the legs except the 3rd (penulti- 

 mate) pair: except the hand, their joints are not more massive than 

 those of the 2nd and 3rd pair of legs. The arm is trigonal, its inner 

 border being prominent and rising into a crest, on the most convex part 

 of which is a short horny plate, called by de Man the " musical ridge " : 

 this border of the arm, as also the inner border and angle of the wrist 

 and the extreme proximal end of the upper border of the palm, is serrated. 

 The palm is nearly as long as the arm and is perfectly smooth and 

 unsculptured, it has a tuft of hair at its extreme distal end, continuous 

 with a thick fringe of hair along the upper border of the dactylus : the 

 dactylus is about two-thirds the greatest length of the palm and has a 

 molariform tooth at its basal end, but there is no such tooth on the 

 immobile finger : the fingers meet only at the distal inbent end. 



In the female and young male the chelipeds are short and slender, 

 a good deal fringed with hair, but unsculptured, and the fingers are 

 longer than the palm. 



In both sexes the legs are alike, the 2nd and 3rd pairs being 

 remarkably long and strong and the 1st and 4th (last) pairs being short 

 and comparatively slender. The 3rd pair, which are the longest of all, 

 are from 2| to nearly 3 times the length of the carapace, the 4th pair 

 are only about 1| times the length of the carapace. In all but the last 

 pair the meropodites carpopodites and propodites are scabrous, the 

 anterior border of all these joints and the distal end of the posterior 

 border of the meropodites being serrated : in the third pair only the 

 posterior border of the propodite is very strongly serrated. 



In the Indian Museum are 7 specimens from Karachi and one from 

 Orissa. In a large male specimen the carapace is 35 millim. long and 

 62 millim. broad. 



The great changes that occur in the chelipeds during the growth 

 of the male indicate that caution is necessary in basing specific distinc- 

 tions on the form of these organs in this genus. 



71. Macrophthalmus convexus, Stimpson. 



Macrophthalmas convexus, Stimpson, Proc. Ac. Nat. Sci. Philad. 1858, p. 97 : 

 Miers, Ann. Mag. Nat. Hist. (5) V. 1880, p. 307 : Haswell, Cat. Austral. Crust, p. 89 ; 



