2 A. Alcock — Carcinological Fauna of India. [No. 1, 



Tribe CYCLOMETOPA, or CANCROIDEA. 



Cyclometopes, Telphusiens and CorystienSy Milne Edwards, Hist, Nat, Crust. I, 

 264 and 363, II. 7 and II. 139. 



Cancroidea and Corystoidea, Dana, U, S, Expl. Exped., Crust, pt, I, pp. 142 

 and 296, 



Cyclometopes and Gorystiens. A, Milne Edwards, Ann. Sci. Nat. Zool. (4) XIY, 

 1860, p, 185. 



Gyclometopa or Cancroidea, Miers, Challenger Brachyura, pp, 106-215. 



Maioidea- corystoidea, pp. 26 and 28; Cancroidea-portuninea, -pp. 27 and 65 ; and 

 Cancroidea-cyclometopa (Cancrini and Xanthini onlj), pp. 412, 421, 428 : Ortmann, 

 Zool, Jahrb,, Syst., etc., VII, 1893-94, 



Oxyrhyncha-corystidse and Gyclometopa or Cancroidea Ortmann, in Bronn's 

 Thier-Eeich V, ii. Arthropoda, pp, 1166 and 1165, 



Carapace variable, either broader than long (almost all Telphiisidse 

 Xantliidse and Portunidse, and some Cancridse) or longer than broad 

 {Corystidae and most Cancridse)^ the antero-lateral borders generally 

 arched, sometimes very strongly so, the postero-lateral borders gene- 

 rally convergent, sometimes very strongly so. Front broadish or broad, 

 horizontal or obliquely deflexed, occasionally prominent (bnt never 

 forming a pointed rostrum with the basal antenna- joints for pillars as 

 in the Oxyrhyncha) . 



Buccal orifice square-cut — only in the Corystidse may its anterior 

 angles be rounded off and a little convergent and its anterior boundary 

 be indefinite : palp of external maxillipeds almost always articulating 

 with the antero-internal angle of the merus. 



Epistome transverse, never long fore and aft, sometimes linear and 

 sunken (not distinguishable in the Corystidse). 



Antennules folding either nearly transversely or longitudinally. 



BranchioB nine on either side, their efferent channels opening on 

 either side of the palate. 



The abdomen of the male occupies all the space between the last 

 pair of legs. 



The genital ducts of the male open on the bases of the last pair of 

 legs. 



The Gyclometopa may be divided into the following 5 families : — 

 Eamily I. Telphusidj;. Carapace usually transverse, broader than 

 long, subquadrilateral or oblate-oval, the antero-lateral borders short, 

 the regions not well delimited (although the cervical suture may be 

 deep and conspicuous) and never areolated. Front broad, not separated 

 from the inner supra- orbital angles, obliquely deflexed (occasionally 

 horizontal), commonly entire (occasionally lobed). 



