586 THE AMERICAN NATURALIST. [Vor. XXXIV. 
B'. Oblique ridge not terminating at carpal cavity, but continued by 
an angular turn to near the superior margin. 
C. A tooth or spine on the inner surface of the carpus of the 
large cheliped. Ridge on inner surface of palm strongly 
produced . . . . U. spinicarpa Rathbun, sp. nov.,' G 
C’. No tooth nor spine on inner surface of carpus. 
Superior surface of palm turned abruptly at right angles 
with outer surface, and forming a flat or concave surface 
U. coloradensis Rathbun, mouth of Colorado River 
D’. Superior surface of eee Samen gradually into outer 
surface . U. gracilis Rathbun, D 
Genus Euchirograpsus Milne Edwards E. americanus A. Milne Edwards, S 
Fic. 3. Po.» 
Fic. 3. — Uca pugilator Fic. 4. — Uca pugilator, inner side of large chela. 
: Fic Gaya aaa carapac 
Genus Euryplax Stimpson . . . . . . . E. nitida Stimpson, G 
Genus Geryon Krøyer . . . . . . . . G. guinguedens Smith, NM 
Genus Speocarcinus Stimpson. 
Key to Species. 
A. Lateral margin of carapace with three notches 
S. carolinensis Stimpson, S 
A’. Lateral margin of carapace with two notches 
S. californiensis (Lockington), D 
THE SPECIES OF GECARCINIDE. 
Genus Cardisoma Lateille n Aen Ge guanhumi Latreille, G 
KEY TO THE GENERA OF THE FAMILY GRAPSIDÆ. 
A. Antennæ covered by the front. 
B. External maxillipeds without a piliferous ridge. 
C. Carapace as long as or longer than broad . 
C'. Carapace considerably broader than long. 
Planes 
1 Type, U. S. Nat. Mus., No. 22,183, Galveston, Texas; Boll, collector. 
