56 A REVISION OF THE ASTACIDA. 
obsoletely serrate, as in the male. The superior border of the meros is 
smooth except at the distal end. The terminal spine of the rib on the 
inner blade of the swimmerets is inside of the posterior margin. The an- 
nulus is quite different from that of the other species of this group, viz. 
O. gracilis, advena, and simulans, and I suspect that this female belongs to a 
species of the C. Bartonii group allied to C. Diogenes and argillicola. 
All the other specimens in the Museum which are referred to C. Caro- 
linus by Dr. Hagen are small specimens. No. 3368, dry female from Georgia, 
L. Agassiz, is certainly C. advena. No, 3567 (No. 1850 of Hagen), a young 
female also from Georgia, resembles C. advena in most respects, but the anten- 
nal scale is too broad near the tip. No. 230, seven young female specimens 
from Mobile, Ala., and No. 275, a very young male from the same locality, 
appear to belong to some species of the C. Barton’ group, rather than to the 
C’. advena group, the tips of the male appendages being strongly recurved. 
I am not certain of the identity of Erichson’s species. Hagen examined 
Erichson’s type (a male of the first form) in Berlin, in 1870, and thought it 
was C. Bartow? Erichson’s description, nevertheless, fits the present species 
very well. The shape of the carapace, the linear areola, the small abdo- 
men, and the crest-like single row of tubercles on the inner side of the 
hand, certainly seem to indicate this species rather than C. Bartoniit. Erich- 
son’s type was collected by Dr. Cabanis, who informed Dr. Hagen that all 
the Astacidze he procured came from near Greenville in the upper part of 
South Carolina. The specimen in the Museum of Comparative Zodlogy here 
referred to C. Carolinus comes from the seaboard at Charleston. The form 
of the male appendages of Erichson’s type would at once prove or disprove 
its identity with C. Barton. If it be the same, the species under consider- 
ation must receive a new name, C. Hagenianus. The unispinous telson of 
Erichson’s type is probably an abnormal condition, not a specific character. 
21, Cambarus gracilis. 
Plate VIII. figs. 4, 4, 4” (first abdominal appendages of male). 
Cambarus gracilis, Buxvy, Bull. Ill. Mus. Nat. Hist., No. I. p. 5, 1876. — Trans. Wis. Acad. Sci., V. 182, 
1882.— Geol. Wis., Surv. of 1873-79, I. 408, 1888. 
Cambarus gracilis, Fores, Bull. Il. Mus. Nat. Hist., No. I. p. 18, 1876. 
Cambarus gracilis, Faxon, Proc. Amer. Acad. Arts and Sci., XX. 141, 1884. 
Male, form I.—Rostrum of moderate length, depressed, broad, excavated, 
foveolate at base; margins raised, punctate, slightly converging from the 
