400 REPORT OF THE COMMISSIONER OF FISHERIES. 
el, Intramedial region narrow, its anterior width about two times its length. 
f. Verges greatly exceeding the third segment of the abdomen. 
g. Tips of verges straight. Second to sixth antero-lateral teeth equi- 
lateral. ea. <-seAn ot cen Sete eee ne Oe A= cera ee C. dane. 
g. Tips of verges curved. Antero-lateral teeth with posterior margins 
longer thanvanterion = -a-eee eae eee eee eee C. arcuatus. 
fi. Verges exceeding the third segment but little, or not at all. .C. larvatus. 
d' Lateralspine less than twice the length of preceding tooth... --- O. exasperatus. 
. Verges reaching the extremity of the abdomen or nearly so. 
d. Antero-lateral region granulate. Lateral spine between two and three times 
a 
length..of preceding tooth 23252-2422 5- eee eee ee aoe ', toxotes. 
d', Antero-lateral region smooth. Lateral spine less than twice the length of 
preceding: tooth. 225s... ncn. th nectar ee oes C. bocourti. 
Ga lnner suUpraorOiial MSsurerOpen sss se see =e eae eee eee C. bellicosus. 
Toward the southern half of its range the true C. sapidus is)more 
or less replaced locaily by a varietal form, C. sapidus acutideus Rath- 
bun, which differs in the possession of an accessory tooth on the inner 
margin of each of the pair of median frontal teeth. This form begins 
to appear in the Gulf of Mexico and is apparently common on the 
coast of Cuba and probably other of the West Indian Islands. 
DISTRIBUTION AND HABITAT. 
The natural range of the blue crab is from Massachusetts Bay to 
some as yet undetermined point on the east coast of South America. 
On the coast of the United States it is common from Cape Cod to the 
southern extremity of Texas, and throughout the greater portion of 
this long coast line it is very abundant. Its favorite habitat is in the 
waters of some bay or at the mouth of a river, and it seems to prefer 
shallow water to that of much depth. Consequently, such bodies of 
vater as Delaware Bay, Chesapeake Bay, and the protected channels 
along the coasts of Virginia and other South Atlantic and Gulf States 
fairly swarm with these creatures. Chesapeake Bay is especially fav- 
orable and has lone been famous, not only for the great number of 
crabs which it produces, but also for their large size and exceptionally 
fine flavor. 
Although the blue crab is essentially an inhabitant of salt water, it 
is frequently found in water that is only slightly brackish or even 
apparently quite fresh. Specimens have been recorded from the Hud- 
son River as far north as Newberg and on credible authority I have 
learned of the presence of an occasional individual in the Potomac 
River and the Eastern Branch opposite the city of Washington. At 
Crisfield, Md., and at other points along both the eastern and western 
shores of Chesapeake Bay, I have frequently observed the blue crab 
in ponds and ditches, often at a distance of a mile or two from the bay 
and in water that was nearly fresh. In such situations it was often 
living in shallow burrows in the banks, but I was unable to determine 
whether these were of its own construction. 
