160 A. Alcock — Garcinological Fauna of India. [No. 2, 



Family I. MAILD^E. 



Macropodiens and Ma'iens, Milne-Edwards, Hist. Nat. Crust. I. 272. 

 Maiinea, Dana, U. S. Bxpl. Exp. Crust. Pt. I. pp. 76 and 77, (and Oncininea.) 

 Maiinea, Miers, Journ. Linn. Soc, Zool., Vol. XIV. 1879, p. 640 ; and ' Challen- 

 ger ' Brachyura, p. 2. 



Basal antennal joint well developed, and occupying all the space 

 between the antennulary fossa and the eye. 



Taking the characters sagaciously suggested by Miers, namely, 

 the relative development of the component parts of the orbit, including 

 basal antennal joint — as the basis of a division, the members of the 

 family Maiidas fall into four natural groups or sub-families as follows : — 



Key to the Sub-families of Maiidae. 



Sub-family I. Inachinse. Eyes without orbits : the eyestalks, 

 which are generally long, are either non-retractile, or are retractile 

 against the sides of the carapace, or against an acute post-ocular spine 

 that affords no concealment. The basal joint of the antennae is 

 extremely slender throughout its extent, and is usually long : — 



Alliance I. Leptopodioida. Basal joint of the antennae usually 

 sub-cylindrical, or at any rate convex ventrally, often independent of the 

 neighbouring structures : the external maxillipeds have the merus 

 narrower than the ischium, and the palp large and coarse, and hence 

 have a somewhat pedifoimi appearance. 



Alliance 2. Inachoida. Basal joint of the antenna? flattened or 

 concave ventrally, and intimately fused with the neighbouring parts ; 

 its antero-external angle often produced to form a spine visible from 

 above : the external maxillipeds have the merus at least as broad as the 

 ischium, and the (small) palp borne at the internal angle of the merus. 



Sub-family II. Acanthonychinse. Eyes without true orbits : the 

 eyestalks, which are very short or sometimes even obsolescent, are 

 either concealed beneath a forwardly- produced supra-ocular spine, or 

 are sunk in the sides of a huge beak-like rostrum ; a postocular spine 

 or process is sometimes present, but is not excavated for the reception 

 of the retracted eye. The basal antennal joint is truncate-triangular. 

 The external maxillipeds have the merus as broad as the ischium. 



Sub-family III. Pisinse. Eyes with commencing orbits, of which 

 one of the most characteristic parts is a large, blunt, usually but not 



