1898.] A. Alcoek — Carcinological Fauna of India. 95 



Orbital margin with the three suture-lines near the outer angle 

 fine and faint but distinct : eyestalks short and thick, eyes small. 



Antennules folding transversely, inter-antennulary septum broad. 



Basal joint of antennae short, touching the front only at their 

 antero-external angle ; flagellum lodged in the orbital hiatus, short (less 

 than the major diameter of the orbit). 



Merus of external maxillipeds with the anterior border almost 

 transverse. 



Chelipeds subequal in both sexes ; fingers pointed, not distinctly 

 hollowed at tip. 



Legs with the upper border of the merus carpus and propus, and 

 the lower border of the merus and propus, sharply carinate or cristate. 



Abdomen of the male five-jointed, the 3-5th somites being fused. 



Medium-size and large crabs. 



Key to the Indian species of Atergatis. 



I. Edge of anterolateral borders of carapace sharp and 

 crest-like, forming a tooth or ridge at the lateral epibran- 

 chial angle : — 



i. Carapace with an even surface, without indications 

 of regions : — 



1. Surface of external maxillipeds almost 

 devoid of hair ; no comb-like tufts of hair 



on the legs ... ... ... A. integerrimus, 



2. Surface of external maxillipeds like a door- 

 mat ; comb-like tufts of thick hair on the 

 under surface of some of the joints of the 



legs ... ... ... ... A, dilatatus. 



ii. Carapace with the surface somewhat lumpy ; 



variegated with spots and confluent blotches ... A,fioridus. 

 II. Edge of antero -lateral borders of carapace thick and 

 blunt; no ridge or tooth at the lateral epibranchial 

 angle ... ... ... ... ... A. roseus. 



20. Atergatis integerrimus (Lam.) 



Cancer integerrimus, Lamarck, Hist. Nat. Anim. sans Vert. V. Crust, p. 272 : 

 Milne Edwards, Hist. Nat. Crust. I. 874 and in Cuvier's Regne An. Crust, pi. xi 

 bis., fig. 1. 



Atergatis integerrimus, De Haan, Faun. Japon. Crust, p. 45, pi. xiv. fig. 1 : 

 Dana U. S. Expl. Exp. Crust, pt. I. p. 158 : Stimpson, Proc. Ac. Nat. Sci. Phila. 

 1858, p. 32 : A. Milne Edwards, Nouv. Arch, du Mus. I. 1865, p. 235 : Miers, Ann. 

 Mag. Nat. Hist. (5) V. 1880, p. 231 : Richters, in Mobius Meeresf. Maurit. p. 145 : 

 F. Muller, Verh. Ges. Basel, VIII. 1886, p. 474 : de Man, Archiv. fur Naturges. LIII. 

 1887, i. p. 244, and Journ. Linn. Soc, Zool., XXII. 1888, p. 24, and Zool. Jahrbuch. 

 Syst. VIII. 1895, p. 496 : A. 0. Walker, Journ. Linn. Soc, Zool., XX. 1890 p. 109 : 



