Curcinoloyical Fauna of India. 153 



Matuta, Fabr., Edw. 



Matuta, Fabricius, Ent. Syst., Suppl. p. 369. 

 Matuta, Milne-Edwards, Hist. Nat. Crust. II. 113. 



Matuta, Miers, Trans. Linn. Soc. Zool. (2) I. 1875-79 (1877) p. 243, and 

 'Challenger' Brachyura, p. 294. 



Matuta, de Man, Notes l.eyden Mus. III. 1881, p. 109. 



Carapace somewhat depressed, usually subcircular, with the 

 postero-lateral borders sharply convergent, and usually with a great 

 horizontal spike at the lateral epibranchial angle, on either side. 



There are usually six more or less distinct tubercles, disposed qnife 

 symmetrically, in the middle of the carapace, and there is commonly 

 an eminence, or even an acute tubercle, iu the front half of the postero- 

 lateral border. 



The front is about as wide as the orbit, and consists of three nearly 

 equal lobes, the middle one of which projects as a laminar rostrum with 

 the end usually bifid or emarginate. 



The orbits are large and roughly reniform : in the middle of the 

 upper border are two short sutures, placed close together ; at the 

 external angle is a wide gap communicating with a deep groove in the 

 pterygostoniian region ; while at the internal angle is a fissure com- 

 municating with the antennulary fossa. The eyestalks are stout but 

 somewhat elongate. 



The antennules fold nearly longitudinally. The antenna? are 

 almost rudimentary, and occupy a space between the basal-antenn alary 

 joint and the lower wall of the orbit. 



The external maxillipeds completely cover the mouth and all tire 

 mouth-parts, up to the level of the front, the patulous efferent branchial 

 orifice being visible only from above. In repose the palp of the exter- 

 nal maxillipeds lies completely concealed within a deep groove in the 

 dorsal face of the long subacute meropodite. 



On removal of the external maxillipeds a deep undivided efferent 

 canal is seen in the roof of the endostome, which groove is closed below 

 by an elongate lamellar process of the first pair of maxillipeds. 



The chelipeds are shaped on the Calappa plan, but are quite 

 singular in having, on the inner face, near the crest of the palm, two 

 raised obliquely-striated areas — one linear, the other broadly oval — 

 which in two species at any rate, and probably in all, are used as strid- 

 uhiting organs. The meropodite, or "arm," has the transverse distal 

 crest low, and only well-pronounced at the outer angle, where there is 

 a prominent lobule. The propodite or "hand" is compressed, but not 

 so much so as in Calappa, and has its upper border cristate, and its 

 outer surface definitely sculptured. The tiugers, as well as the rest of 



the chelipeds, are quite symmetrical. 



158 



