1895.] A. Alcock — Carcinological Fauna of India. 159 



The classification proposed in this paper is in many respects a 

 reversion to the older authors. 



For a most interesting and instructive historical and critical review 

 of the Oxyrhyncha as a whole, I would refer to the Introduction of 

 Miers' paper, already cited, in the Journal of the Linnasan Society, 

 Zoolog}-, Vol. XIV. J 879, pp. 634-642. 



I have only to add that as almost all the new species described in 

 this paper have been dredged by the ' Investigator,' they will be 

 figured in next year's issue of the " Illustrations of the Zoology of the 

 ' Investigator.' " 



Tribe OXYRHYNCHA or MAIOIDEA. 



Oxyrinques, Oxyrinchi, Latr. Hist. Nat. Crust, et Insect, torn. VI. p. 85. 



Oxyrhinques et Canceriens Cryptopodes, Milne-Edwards, Hist. Nat. Crust, torn. I. 

 pp. 263, 368. 



Maioidea or Oxyrhyncha, Dana, U. S. Expl. Exp. Crust. Pt. I. pp. 66, 67 and 75. 



Oxyrhyncha, Miers, Journ. Linn. Soc, Zool., Vol. XIV. 1879, p. 634; and 

 ' Challenger' Brach\ura, p. 2. 



Carapace more or less narrowed in front, and usually produced to 

 form a rostrum : branchial regions considerably developed, hepatic 

 regions small. Epistome usually large ; buccal cavity quadrate, with 

 the anterior margin usually straight. Branchia3 almost always nine in 

 number on either side*: their efferent channels open at the sides of 

 the endostome or palate. Antennules longitudinally folded. The 

 palp of the external maxillipeds is articulated either at the summit or 

 at the antero-internal angle of the meropodite. The external genitalia 

 of the male are inserted at the bases of the fifth pair of trunk-legs. 



The Oxyrhyncha may be sub-divided into two families, namely : — 



(1) the Maiidae, in which the basal joint of the antennae is well 

 developed, and in which it is exceptional to find the chelipeds vastly 

 longer than the other legs ; 



and (2) the Parthenopidee, in which the basal joint of the antennae 

 is very small, and is embedded between the front and the floor of the 

 orbit ; and in which it is exceptional not to find the chelipeds vastly 

 longer and vastly more massive than the other legs. 



* Encephaloides is the only Oxyrhynch known to me in which the branchiae are 

 less than nine in number on either side : in Encephaloides the reduction, both in 

 size and number, of the anterior branchiae seems to be due to the enormous 

 development of the four posterior branchiae. 



