Revision of the Nomenclature of the Brachyura. 161 



days it was not deemed unpardonable to change 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 : 



Potamon 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] 

 = Thelphusa fluviatilis Latreille, 1819, not C. fluviatilis Herbst, 

 1785. 



Charybdis de Haaii, 1833, for Goniosoma A. Milne Edwards, 

 1860, on account of Charybdea Peron and Lesueur, 1809. Goni 

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



1834, for a genus of Arachnida. 



Pilho Bell, 1835, for Othonia Bell, 1836, without explanation. 

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



1835, Vermes.) 



Gecareoidea Milne Edwards, 1837, for Pelocardnus Milne Ed 

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

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



Xanthodius Stimpson, 1859, if considered congeneric with Lep- 

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

 take precedence, and not be treated as a synonym or a subgenus 

 of Leptodius* 



Paulson, 1875, gives Cryptochirus Heller as a synonym of 

 Lithoscaptas A. Milne Edwards, but the former genus was de 

 scribed in 1861, the latter in 1862. 



Arctopsis Lamarck, 1801 (description insufficient ?) is retained 

 by Miers, 1879 and 1886, as a subgenus of 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 biaculeata (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 authors 

 to the same new genus is that of Aidacolambrus, a name attributed 



*Leptodius is made a synonym of Xanlho by Ortmann, Zool. Jahrb., 

 Syst., VII, Heft 3, 443, 1893. 



38 .BioL. Soc WASH., VOT, XI, 1897 



