140 THE AMERICAN NATURALIST. [VoL. XXXIV. 
Genus Callinectes Stimpson. 
. Key to Species. 
A. Front with four intraorbital teeth. 
B. Median pair of frontal teeth without an accessory tooth 
. sapidus Rathbun NMSG 
B'. Median pair of frontal teeth, each with an accessory tooth on its 
inner margin . . ., C. sapidus acutidens Rathbun SG 
A’. Front with six intraorbital ene 
B. Intramedial region broad, its anterior width about three times its 
length. Posterior TEN of antero-lateral teeth longer than the 
anterlot . . . C.ornatus Ordway SG 
B'. Intramedial region narrow, its anterior c idth about twice its length. 
econd to sixth antero-lateral teeth equilateral 
C. dane Smith SG 
Genus Portunus Fabricius. 
Key to Spectes. 
A. Carapace wide; antero-lateral margin the arc of a circle with long 
radius, whose center is near the posterior margin of the carapace 
Subgenus Portunus = Neptunus de Haan 
Fic. 3. — Callinectes sapidus. 
B. First eight lateral spines or teeth subequal. 
C. Front with six intraorbital teeth P. sayi (Gibbes) WMSG 
c Front with eight intraorbital pun 
P. gibbesii (Stimpson) MSG 
B’. Second, fourth, and sixth lateral teeth or spines smaller than the 
others P. xantusii (Stimpson) PD 
A’. Carapace narrow ; beo E, narii the arc of a circle with short 
radius, whose center is near the center of the cardiac region 
Subgenus Achelous de Haan (including Helena and Amphitrite de Haan). 
