KINOSTERNIDA. — CXXL 207 
307. CHELYDRA Schweigger. (xéAvs, turtle; Udep, water.) 
603. C. serpentina (L.). CoMMON SNAPPING TURTLE. Dusky 
brown ; head with dark spots. L. 25 or more. Canada to Equador, 
everywhere abundant about water. 
308. MACROCHELYS Gray. (paxpos, large; yedvs.) 
604. M. lacertina (Schweigger). ALLIGATOR SNAPPER. Black- 
ish ; head with many fleshy slips. Gulf States, N. to Wis. L. 40 
or more ; “ perhaps the most ferocious, and, for its size, the strong- 
est of reptiles.” 
Famiry CXXI. KINOSTHRNIDA. (THE Box TuRTLEs.) 
Carapace rather long and narrow, the outline usually rising 
gradually from the front to a point beyond the centre of the shell, 
then abruptly descending; the bulk of the body therefore thrown 
backward ; margin of the carapace turning downward and inward 
rather than outward; plastron proportionally large, covered with 7, 
9 or 11 horny plates, the anterior pair coalescing into one; anterior, 
and sometimes also posterior lobe of plastron, often movable upon 
the fixed central portion ; head pointed ; jaws usually strong; eyes 
far forward ; limbs slender ; feet short. 
Turtles of small size, chiefly American. 
a. Plastron with its anterior and posterior lobes nearly equal in length, both 
freely movable and capable of closing the shell; posterior lobe emarginate 
behind, its angles rounded ; carapace without traces of keel in adult. 
KINOSTERNON, 309. 
aa. Plastron with its posterior lobe longer than anterior, truncate behind, its 
posterior angles not rounded; lobes of plastron little movable, incapable 
of closing the shell; carapace more or less keeled, at least when young; 
head very large, with strong jaws. . . . . . AROMOCHELYS, 310. 
309. KINOSTERNON Spix. (kwéw, to move ; arépvov, breast.) 
605. K. pennsylvanicum (Bosc). Mup Turt ie. Shell dusky 
brown ; head dark, with light dots. L.4. N. Y. to Fla. 
310. AROMOCHELYS Gray. (dpwya, odor; yédvs.) 
606. A. odoratus (Latreille). Musk TurtTie. SrTrinK-por. 
Shell dusky, clouded, sometimes spotted; neck with two yellow 
stripes, one from above eye, the other from below; head very 
large with strong jaws; carapace with traces of a keel, but the 
plates not imbricated in the adult ; no point at symphysis of upper 
jaw ; odor strong, musky. L.6. E. U.S., abundant, W. to N. Il. 
(Rice & Davis.) 
607. A. carinatus Gray. Plates of carapace overlapping more 
or less, each one edged with black and marked with radiating black 
stripes; neck unstriped; a point at symphysis of upper jaw. La., 
N. to N. Ill. (Rice & Davis.) 
