662 ROCEEDINGS OF THE NATIONAL MUSEUM. 



In some respects C. montezumxv dnfiesii shows an approach toward 

 this species, but the two forms can not be coiifouiMled on account of 

 the greater slenderness of C. chapalafius, the great length of the ros- 

 tral and postorbital spines, etc. C. shnfeldtii is distinguished from C. 

 chapalanKS by the presence of lateral spines on the carapace, broader 

 rostrum, differently shaped male appendages, etc. 



Genus ASTACUS Fabricius (s. 3.).' 



< Cancer Linn.eus, Syst. Nat., 10th ed., I, p. 625, 1758. 



<^Astacus Fabricius, Syst. Entoniol., p. 413, 1775; Species Insectoruni, I, p. 514, 



1781 ; Mantissa Iiisectorum, I, p. 331, 1787 ; Entomol. Syst. emend., II, p. 478, 



1793; Suppl. Entomol. Syst., p. 382, 1798. 

 <^Astacu8 Latreille, Considerations G<5nerales, p. 101, 1810 {Astacus fluvialiJls 



Fabricius = Crt»u(T astacus Linn.eus, specified as tlie type, p. 422). 

 <^Astacu8 Leach, Edinb. Encycl., VII, p. 398, 1814; Trans. Linn. Soc. London, 



XY, pp. 336, 343, 1815. 

 <^ Potamohius Leach, Samonelle's Entomologist's Useful Compeudinii), p. 95, 



1819 (Type, rotamobiua ^ttitfiatilis=: Cancer asiuciis Linn.eus). 

 <^ Astacus Milne-Edwards, Hist. Nat. Crust., II, p. 329, 1837. 

 z= Astacus (subgenus) Erichson, Arch. f. Naturgesch., 12ter .Tahrg., I, p. 90, 1846. 

 Type, Cancer astacus Linnj^us. 



The genus Astacus, as first established by Fabricius,^ included eight- 

 een species. The dismemberment of this heterogeneous assemblage 

 was begun by Fabricius himself in 1781,' by the removal of three 

 species to the genus Squilla. In 1798,'* he eliminated several other 

 species from Astacus, forming for their reception the genera Crangon, 

 Alpheus, Fahcmon, and PaUnuyus. As left by its founder in 171)8, the 

 genus Astacus contained only five of the original species, namely, A. 

 marimis { = Cancer gammarus Linniieus), A. fluviatilis { = Cancer 

 astacus Liniueus), A. coeriilescens, A. fulgens, and A. norvegicits. Two 

 of these, coeriilescens and fulgens, are indeterminable. In 1 8 1 Latreille,-' 



'Those who accept the genera defined by polynomialists after the year 1758 will 

 ascribe the genus Js<ac«8 to Gronovius, 1764 (Zoophyhiciuni Gronovianum, Fascic- 

 ulns II, p. 227). Even as early as 1760 Gronovius (Acta Helvetica, IV, p. 23) assigned 

 Calatca strUjosa jiolynomially to Astacus, using Astacus iu its old pre-Liuna'iin sense. 

 In 1772 Pallas, a binomialist, in his "Spicilcgia Zoologica," Fasciculus IX, p. 81, used 

 the combination Astacus dauuricus in treating of the Danrian crayfish. Pallas wrote 

 in Latin, and it is evident that Astacus was here used merely as the Latin word for 

 "crayfish" or " lobster," and not as a technical generic name ; for the diaguosis of the 

 Danrian crayfish is headed " iJescriptio Cancri danurici,'^ conformably with Liuna-us's 

 nomenclature. Even if one forces the point and carries the genus Astacus back to 

 Pallas, 1772, it will not make the Danrian crayfish the type of the genus, since the 

 description of the Danrian crayfish is a comparative one, the lesser European Asta- 

 cus [Astacus nostras minor'], i. e.. Cancer astacus Linn:T>us, serving as the standard for 

 comparison. To regard as a type the thing compared, rather than tlie standard of 

 comparison, would be a manifest absurdity. 



-Syst. Ent., 1775. 



^Species Insectorum. 



■•Suppl. Ent. Syst. 



''• Consid6ration8 Gen(^rales sur I'Ordre Naturel des Animaux composant les Classes 

 des Crustaccs, des Arachnides, et des Insectes. 



