84 A KEVISION OF THE ASTACID^. 



34. Cambarus extraneus. 



Cambarus extraneus, ILu.fn. III. Cat. Mus. Comp. Zool., No. III. p. 73. PI. I. figs. 88, 89, PI. III. fig. 156, 



L870 



teus, Faxox, rroc. Amer. Acid. Arts and ^ci.. XX. 113, 1S81. 



Known Localities. — Tennessee River near the border of Georgia. Etowah 

 River, Rome, Ga. 



Cambarus extraneus, Girardianus, Jordani, cornutus, and hamulalus agree in 

 combining the toothed rostrum of the C. affinis group with' male appendages 

 formed as in the C. Barionii group. The third pair of legs alone are hooked. 

 G. hamulatus is at once distinguished by its rudimentary eye-stalks, the great 

 length of the posterior segment of the carapace, and long and slender chela?. 

 It has the superficies of G. pelluetdus. C. cornutus has strong, erect, lateral 

 rostral teeth, and very thick antennal flagellum, heavily bearded on inner 

 side. C. Jordani has a narrow areola with but a few scattered dots, and the 

 antennal scale is broadest toward its tip. G. extraneus and C. Girardianus 

 have a wide areola thickly sown with dots; they are closely related, but may 

 be separated as follows. In G. extraneus the areola is broader and shorter 

 than in C. Girardianus; while in C. extraneus the section of the carapace 

 behind the cervical groove is never more, usually less, than one third of 

 the entire length of the carapace from tip of rostrum to posterior border, 

 in C. Girardianus this section of the carapace is more than one third of the 

 length of the entire carapace. The punctation of the carapace is much 

 coarser in C. extraneus than in C. Girardianus. The lateral spine of the 

 carapace is very prominent in G. extram us, rudimentary in C. Girardianus. 

 In C. Girardianus the external orbital angle is very prominent, and ends 

 in an acute spine with a corneous tip; the fingers are longer in propor- 

 tion to the hand than in 0. extraneus. The distal end of the mcros has 

 a single spine on the upper edge in C. Girardianus; C. extraneus has two 

 obliquely placed. 



Of C. extraneus I have seen nine specimens, of G. Girardianus five, of 

 (,'. Jordani one, of C. hamulatus six. Among these are males of the second 

 form witli the first abdominal appendages articulated and not articulated, 

 but no males of tlie first form. 



The larger female mentioned by Bagen, p. 74, is G. spinosus Bundy. 

 The largesi Bpecimen of C. extraneus seen by me, a male, form II., with 

 articulated lust abdominal appendages, is in the possession of Butler Uni- 



