26 A REVISION OF THE ASTACID/E. 
4. Cambarus Clarkii. 
Cambarus Clarkii, Grrarp, Proc. Acad. Nat. Sci. Philad., VI. 91, 1852. 
Cambarus Clarkii, Hagen, Ul. Cat. Mus. Comp. Zodl., No. TIL. p. 39, Pl. I. figs. 7-10,.99, 100, Pl. IT. figs. 
133, 134, Pl. IIL. fig. 142, Pl. IV. (this figure is copied on a reduced scale in Huxley’s ‘ Crayfish,” 
p- 248, 1880), 1870. 
Jumbarus Clarkii, Faxon, Proc. Amer. Acad. Arts and Sci., XX. 136, 1884. 
Known Localities. — Texas: between San Antonio and El Paso del Norte 
(Girard); San Antonio; Clear Creek, Waller Co. (Coll. U. 8. Nat. Mus.). 
Louisiana: New Orleans; Tangipahoa River (Coll. U. S. Nat. Mus.).  Mis- 
sissippi: Ocean Springs, Jackson Co. (Coll. U. S. Nat. Mus.), Alabama: 
Mobile. Florida: Pensacola (Coll. U. 8. Nat. Mus.) ; three miles below Horse 
Landing, St. John’s River. Ohio: Olmsted [?]. 
Girard’s specimens were collected between San Antonio, Texas, and El 
Paso del Norte, by John H. Clark, of the U.S. Mexican Boundary Comnnis- 
sion. The original description of the species is hardly sufficient for determi- 
nation, but fortunately Dr. Hagen was able to identify the species by an 
examination of Girard’s types, which were probably lost in the great fire 
at Chicago, whither they were sent to Dr. Stimpson. <A full description 
of C. Clarkii is given on page 39 of Hagen’s Monograph. 
In specimens collected by Edward Palmer at San Antonio, Texas, the 
carapace is smoother than in the form commonly received from New Orleans 
and Mobiie, with more prominent lateral and postorbital spines. The ros- 
trum tapers much less than in the form from farther east, the sides being 
more nearly parallel. The areola, moreover, is not entirely obliterated in 
the middle, but forms a linear area about as wide as in C. troglodytes. The 
male sexual appendages do not differ from those of the Louisiana speci- 
mens. This is probably the form described by Girard. 
In this connection it is interesting to note that in young individuals of 
this species eight millimeters long, taken from beneath the abdomen of a 
female from New Orleans, the areola is proportionally even wider than in the 
San Antonio specimens. 
In a male, form II., 60 mm. long, collected by J. A. Allen in St. John’s 
River, Fla., the areola is like that described in the San Antonio specimens, 
and the distal margin of the proximal segment of the telson is armed with 
three or four spines on each side. The carapace is smooth, 
A female specimen, 92 mm. long, in the Academy of Natural Sciences of 
Philadelphia (No, 654), from the Smithsonian Institution, without locality, 
