NO. 1136. OBSERVATIOXS ON THE ASTACIB^E—FAXOX. 6(13 



ill a "Table ties Genres avec I'mdication de I'espece qui leiir sert de 

 tyi)e," designated ^4., /?w?;^rt.^^7^s as the type of the genus >4sfrf6'»,s. In 

 1814 and 1815 Leaeli ' farther curtailed the genus by removing .4. nor- 

 vcfiicuH as the type of the new genus Xephrop.s. The genus A.stacn.s, 

 thus restricted, retained only two of tlie valid original species, namely, 

 A. marinus (the P^uropeau lobster) and A. fiiiriatili.s (the common Euro- 

 pean crayfish). In 1819- Leach went a step further, and separated 

 the crayfishes from the lobster, instituting a new genus PotamohinH 

 for the former, leaving the latter as the representative of the restricted 

 genus Astacus. This restriction of Astacus to the marine species is 

 nullified by Latreille's specification o\' A.fin'iatilis as the type of Asia 

 cus in 1810.' In 1837 Milne-Edwards^ did essentially the same thing 

 that Leach had done in 1811), but he left the crayfishes in Astacus, and 

 made the lobster the type of the new genus Homarns. This being in 

 accord with Latreille's designation of A. JinriaiUis as the type of ^4."fra- 

 cws, the European lobster should be called by the modern rules of 

 nomenclature (restoring the Linna'an specific name) Homarns (lammarus 

 (Linna'us), while the European crayfish, as Astacus astacus (Linnaeus), 

 stands as the type of the genus Astacus. 



Mr. T. I^. E. Stebbing-' argues that Latreille, in his "Table des Genres 

 avec I'indication de Tespece (]ui leur sert de tyjje,' jjrobably designated 

 Astacus fl III' iatUis "not as the tyj)e, but merely as a type, an example," 

 of the genus Astacus, and that Leach's restriction in 1819 was tiiere- 

 fore valid. As I understand it, the French word 'type' means ' model,' 

 'type,' or 'standard,' not 'example' or 'illustration' (Gallice exempU). 

 I see no reason for going l)ehind Latreille's plain words, to indulge in 

 uncertain speculation concerning his possible meaning. If Mr. Steb- 

 bing is unwilling to allosv Latreille the use of the word 'type' in its 

 technical sense, by what 'statute of limitation' will he fix the year 

 when the word acquired that meaning? Even if it be admitted that 

 there is some doubt concerning the significance of the word 'type' as 

 employed by Latreille, the benefit of the doubt should, by a reasonable 

 ruling applicable to all such cases, be given to a long-established termi- 

 nology. Between 1819 and 1893, the date of Stebbiug's "History of 

 the Crustacea," the name Potamohms was applied to the crayfishes but 

 thrice, so far as I know, namely, by Adam White in his "Catalogue of 

 British Crustacea,"' 1850, and in his "Popular History of British Crus- 

 tacea," 1857, and by G. B. Sowerby in his continuation of Leach's 

 " Malacostraca Podophthalma Britannia'," 1875. " But," continues Mr. 

 Stebbing, "if it be insisted that Latreille here intended to set up the 

 crayfish as technically type of the genus, in preference to the lobster, 

 of which his book makes no mention, the answer is simple. His inten- 



' Edhab. Eucycl.. VII, p. 398; Trans. Linn. Soc. London, XV, pp. 33G, 343. 

 " Samouelle's Entonioloifist's Useful Compondinm. p. 95. 

 »F. H. Herrick, Bull. II. S. Fish Comni. for 1895, p. 9. 

 ••Hist. Xat. des CrustacM's, II, p. 329. 

 f' Natural Science, IX, 1896, p. 40. 



