48 A REVISION OF THE ASTACIDA. 
C. Carolinus, and C. gracilis resemble C. Diogenes of Group III. in the general 
form of body, linear areola, small antennal scale, broad chela, ete. The fore 
border of the carapace is angulated behind the antenne in C. simulans, 
C. Mexicanus, C. Cubensis, and C. gracilis; not angulated in C. advena and 
C. Carolinus. The rostrum is armed with small lateral teeth in C. Cubensis ; 
in the other species of this group the rostrum has no lateral teeth. 
Of the species belonging to this group, Hagen knew only C. advena and 
C. Carolinus. These were placed by him, as aberrant forms, in Group I]. 
(C. Bartonit). 
Rostrum with small lateral teeth, areola broad. C. Cudensis. 
Areola of moderate width. Chele subcylindrical. C. Mevicanus. 
Areola narrow. Antennal scale large and broad. C. simulans. 
rostrum washout lsterelvectt ( Front margin of carapace angulated 
behind antenne. C. gracilis. 
Areola linear, or obliterated in the middle. : IJ 
Front margin of carapace not angu- 
lated. C. advena, C. Carolinus. 
t] 
16. Cambarus simulans. 
Plate I, fig. 2, Plate VIII, tigs. 3, 3’, 3a, 3a’. 
Cambarus simulans, Faxon, Proc. Amer. Acad. Arts and Sci., XX. 112, 1884. 
Male, form I.—Rostrum broad, deeply excavated; margins raised into 
sharp crests, which overhang the base of the sides of the rostrum, converging, 
sinuated before the tip to form the short acumen; no lateral spines; the 
acumen is barely margined. Post-orbital ridges subacute in front, divergent 
and ending in slight ecallosities behind. Carapace ovate, narrowing in front, 
gastric. area smooth, cardiac area lightly punctate, sides granulate; anterior 
border notched behind the antennz ; cervical groove sinuate, split on the 
sides, with a minute terminal branchiostegian spine; no lateral spine; areola 
more than one half as long as the distance from the point of the rostrum to 
cervical groove, narrow, carinate, expanding into an anterior and a posterior 
triangular field; two longitudinal dotted lines run along the areola from the 
anterior triangle to the posterior triangle, which is irregularly and sparsely 
dotted. Abdomen broad, shorter than carapace, punctate, posterior margins 
of pleura obliquely convex; hind margin of anterior segment of telson bi- to 
multi-denticulate on each side, posterior segment short, hind border almost 
straight; median rib of inner plate of swimmeret ends inside of the mar- 
gin. Basal segment of antennule with a spine below. Antenne shorter than 
