OBSERVATIONS ON THE ASTACIDJE—FAXOX. 663 



in a " Table des Genres avec Pindication de l'espece qui leur sert de 

 type," designated A.fluviatilis as the type of the genus Astacus. In 

 1814 and 1815 Leach ' further curtailed the genus by removing A. nor- 

 vegicus as the type of the new genus Nephrops. The genus Astacus, 

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

 A. marinus (the European lobster) and A. fluviatiiis (tbe common Euro- 

 pean crayfish). In 1819 2 Leach went a step farther, and separated 

 the crayfishes from the lobster, instituting a new genus Potamobius 

 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 of A. fluviatiiis as the type of Asta- 

 cus in 1810. 3 In 1837 Milne-Edwards 4 did essentially the same thing 

 that Leach had done in 1819, but he left the crayfishes in Astacus, and 

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

 accord with Latreille's designation of A. fluviatiiis as the type of Asta- 

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

 nomenclature (restoring the Linmiean specific name) Homarus gammarus 

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

 stands as the type of the genus Astacus. 



Mr. T. E. E. Stebbiug f1 argues that Latreille, in his "Table des Genres 

 avec Pindication de l'espece qui leur sert de type,' probably designated 

 Astacus fluviatiiis "not as the type, but merely as a type, an example," 

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

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

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

 I see no reason for going behind Latreille's plain words, to indulge in 

 uncertain speculation concerning his pos.sible meaning. If Mr. Steb- 

 bing is unwilling to allow 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 Stebbing's "History of 

 the Crustacea," the name Potamobius 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- 



1 Edinb. Encycl., VII, p. 398 ; Trans. Linn. Soc. London, XV, pp. 336, 343. 



2 SamoTielle's Entomologist's Useful Compendium, p. 95. 

 3 F. H. Herri ck, Bull. U. S. Fish Comm. for 1895, p. 9. 



4 Hist. Nat. des Crustac<%, II, p. 329. 

 6 Natural Science, IX, 1896, p. 40. 



