214 REPORT OF NEW JERSEY STATE MUSEUM. 
Family CHELYDRIDEZ. 
The Snapping Turtles. 
Carapace high in front, low behind, covered with epidermal 
shields, comparatively small and with serrated posterior border. 
Neural plates broader than long, forming a complete series. 
Pygals 1 or 2. Marginal plates 23. Plastron small, cruciform, 
and with 9 plates besides very narrow bridge, and articulating 
with carapace by gomphosis. Abdominal shields not meeting 
on median line, separated from marginals by a series of infra- 
marginals. Shell attains complete ossification but late in life. 
Head and neck very large. Neck bending in a sigmoid curve in 
a vertical plane, completely retractile. Jaws strongly hooked and 
powerful. Chin with 1 or more pairs of small dermal appendages. 
Parietals prolonged downwards, forming a suture with ptery- 
goids, or separated from latter by interposition of epipterygoid. 
Pterygoids narrow in middle, in contact on median line. 
Nuchal plate with long costiform processes underlying marginals. 
Outer border of tympanic cavity deeply notched. Mandible with 
articulary concavities. Temporal region incompletely roofed 
over, no parieto-squamosal arch. Squamosal widely separated 
from parietal. Dorsal vertebrze and ribs immovably united and 
expanded into bony plates forming carapace. A complete series 
of marginal bones connected with ribs. Cervical vertebrze with- 
out or with mere indications of transverse processes. Centrum 
of last cervical articulating with centrum of first dorsal, second 
and third opisthoccelous, fourth amphicyrtous and rest proccelous. 
Caudal vertebrze mostly opisthoccelous. Epiplastra in contact. 
with hyoplastra. Entoplastron, if present, oval, rhomboidal, or 
T-shaped. Pelvis not anchylosed to carapace and _ plastron. 
Pubic symphysis widely separated from ischial. Phalanges with 
condyles. Claws 5-4, strong, outer toe clawless, and web small. 
Tail long, crested above. 
Large fierce and powerful turtles of great strength and voracity. 
A single genus and species within our limits. 
