$4 A REVISION OF THE ASTACIDA. 
34. Cambarus extraneus. 
Cambarus extraneus, Wacen, Ill. Cat. Mus. Comp. Zool., No. III. p. 73, Pl. I. figs. 88, 89, Pl. ITT. fig. 156, 
1870. 
Cambarus extraneus, Faxon, Proc. Amer. Acad. Arts and Sci., XX. 145, 1884. 
Known Localities. — Tennessee River near the border of Georgia. Etowah 
River, Rome, Ga. 
Cumbarus eaxtraneus, Girardianus, Jordau, cornutus, and hamulatus agree in 
combining the toothed rostrum of the C. afins group with male appendages 
formed as in the @ Bartonii group. The third pair of legs alone are hooked. 
C. hamulatus is at once distinguished by its rudimentary eye-stalks, the great 
leneth of the posterior segment of the carapace, and long and slender chele. 
It has the superficies of C. pellucidus. C. cornutus has strong, erect, lateral 
rostral teeth, and very thick antennal flagellum, heavily bearded on inner 
side. C. Jordan’ has a narrow areola with but a few scattered dots, and the 
antennal scale is broadest toward its tip. C. extraneus and C. Girardianus 
have a wide areola thickly sown with dots; they are closely related, but may 
be separated as follows. In C. extraneus the areola is broader and shorter 
than in C. Girardianus ; while in C. eatraneus 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 C. extraneus, 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 (C. eztraneus. The distal end of the meros has 
a single spine on the upper edge in ©. Girardianus ; C. extraneus has two 
obliquely placed. ; 
Of C. extraneus I have seen nine specimens, of C. Girardianus five, of 
C. Jordani one, of C. hamulatus six. Among these are males of the second 
form with the first abdominal appendages articulated and not articulated, 
but no males of the first form. 
The larger female mentioned by Hagen, p. 74, is C. spinosus Bundy. 
The largest specimen of OC. extraneus seen by me, a male, form II., with 
articulated first abdominal appendages, is in the possession of Butler Uni- 
