Revision of the Nomenclature of the Brachi/ura. 161 



days it was not deemed unpardonable to cliange the type of a 

 genus. 



5. Earlier names neglected. — A recent example of the abandon- 

 ment of a valid name is the case of Holometopus Milne Edwards, 

 1853, which is a constituent of de Man's subgenus Episesarma of 

 later date, 1895. Other names which have been laid aside with- 

 out sufficient reason are as follows : 



Polamon Savigny, 1816, for Thelphusa Latreille, 1819. Potamon 

 was restored by Ortmann, Zool. Jahrb., Syst., IX, Heft 3, 445, 

 1896. Its type species is Cancer potamios Olivier, an 12 [1803-1804] 

 = Thelp)husa fluviatilis Latreille, 1819, not C. fluviatilis Herbst, 

 1785. 



Charyhdis de Haan, 1833, for Goniosoma A. Milne Edwards, 

 1860, on account of Charyhdea Peron and Lesueur, 1809. Goni- 

 osoma was itself used by Perty, Delect. An. Art., 201-202, 1830- 



1834, for a genus of Arachnida. 



Piiho Bell, 1835, for Olhonia Bell, 1836, without explanation. 

 (Othonia, Johnston, Loudon's Mag. Nat. Hist., VIII, March, 



1835, Vermes.) 



Gecarcoidea Milne Edwards, 1837, for Pelocarcinus Milne Ed- 

 wards, 1853, on account of Gecarcinus Leach, 1814. Gecarcoidea 

 Avas restored by Ortmann, Zool. Jahrb., Syst., VII, Heft 5, 1894. 



Xanthodlus Stimpson, 1859, if considered congeneric with Lep- 

 todius A. Milne Edwards, 1863, as it is by some writers, should 

 take precedence, and not l)e treated as a synonym or a subgenus 

 of Lej)todius.^ 



Paulson, 1875, gives Cryptochlrus Heller as a sNnionym of 

 Lithoscaptns A. ]\Iilne Edwards, but the former genus was de- 

 scribed in 1861, the latter in 1862. 



^/Ttops/.s Lamarck, 1801 (description insufficient?) is retained 

 by Miers, 1879 and 1886, as a subgenus o? Pisa Leach, 1814 ; but if 

 Arctopsis be used at all, which seems unwarranted, it must take 

 precedence of Pisa. The type species of both is supposed to be 

 the same ; its earliest indisputable name is biacideata (Montagu). 

 Tetraodon, which Miers makes the type of the subgenus Pisa, was 

 not put by Leach into Pisa until 1815. 



An example of the same name being applied by two autliors 

 to the same new genus is that oi Aulai'.olambrus, a name attril)uted 



*Leptod'iUS is made a synonym of Xnnlho hy Ortmann, Zool. Jahrb., 

 Syst., VII, Heft 3, 44;3, 1893. 



38— £ioL. Soc Wash., Vol XI, 1897 



