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Key to the species: 

 Ratio of length of carapace to greatest breadth (posterior teeth 



not included) i : 1.4 — 1.5, antero-lateral teeth decreasing in 



size from external orbital angle to penultimate tooth. Merus 



of external maxilHpeds longer than broad, slightly produced 



at antero-external angle C. nitidus A. Milne-Edwards. 



Ratio of length of carapace to greatest breadth as i : 1.7 — 1.8, 



middle antero-lateral teeth somewhat larger than the other 



ones. Merus of external maxillipeds broader than long, with 



the antero-external angle greatly produced C. inaeqtialis Rathbun. 



I. Catoptrus nitidus A. Milne-Edwards. PI. 9, Fig. 4. 



1870. Catoptrus nitidus A. Milne-Edwards. Ann. Sc. Nat. (5), t. 13, p. 82. 



1 888. Goniocaphyra truncatifrons de Man. Arch. Naturgesch., Jahrg. 53, i., p. 339, pi. 14, f. i. 



1890. Goniocaphyra truncatifrons [= Catoptrus nitidus) de Man. Notes Leiden Mus., v. 12, p. 67. 



1894. Catoptrus nitidus Ortmann. Zool. Jahrb., Syst., Bd 7, p. 687. 



1894. Goniocaphyra sp. Zehnter. Rev. Suisse Zool., t. 2, p. 163, pi. 8, f. 12. 



1900. Catoptrus nitidus Alcock. Journ. As. Soc. Bengal, v. 69, prt 2, p. 307. 



1900. Goniocaphyra truncatifrons Borradaile. Proc. Zool. Soc. London, 1900, p. 577. 



1906. Catoptrus nitidus (part) Laurie. Rep. Pearl Oyster Fish. Ceylon, prt 5, p. 422. 



191 1. Catoptrus nitidus Rathbun. Transact. Linn. Soc. London (2), v. 14, p. 239. 



Stat. 144. Salomakiee Island, south of Halmaheira. Depth 45 m. i cf juv. 



Stat. 154. o°7'.2N., I30°25'.5E. North of Waigeu Island. Depth 59 — 83 m. i cf. . 



Laurie has taken the trouble of comparing his specimen most attentively with those of 

 Alcock and de Man and with the type specimen of C. inaeqtialis and concludes, that Miss 

 Rathbun's species most probably is a synonym of the present one. He adds that Miss Rathbun 's 

 photograph "gives an excellent impression of the present specimen", but as the ratio of the 

 length of the carapace to the greatest breadth is given as i : 1.51 we are again inclined to refer 

 his specimen to C. nitidus. Lately Miss Rathbun (191 i), in comparing a series of no less than 

 47 specimens belonging to both species, enumerates 9 points of difference, all of which, save 

 the third (the granulation of the hepatic regions of the carapace is in my material rather finer 

 and more regularly in C. nitidus), I can wholly confirm. 



In her first diagnosis Miss Rathbun remarks, that C. inaequalis is narrower than C. nitidus, 

 but this statement must be a sHp, for in her paper of 1 9 1 1 the reverse is expressly stated 

 to be the case. This character at once demonstrates itself on comparing figs. 4 and 5 (pi. 9) 

 and is very obvious, the ratio of length of carapace to breadth being i : 1.44 in my larger 

 specimen of C. nitidus and i : 1.82 in C. inaequalis^). The antero-lateral margins of.the carapace 

 of the first species show five teeth (including the external orbital angle, but not the last strong 

 spine), regularly decreasing in size (see fig. ^a) backward, but in de Man's type specimen of 



i) In the type specimen of Miss Rathbun the ratio, according to text, becomes i : 1.5 1 (exactly the same as in Laurie's 

 specimen, which is referred to C. iiiliiius), the photograph gives a ratio of I : 1.62. 



31 



