LADY TURTLE. 665 
their habits are remarkably similar. C. marginata ranges as far 
north as Lake Superior, and, in the latitude of Ann Arbor, Michigan, 
has been found out of winter quarters as late as October 22, and in the 
spring on March 3l. They undoubtedly attain toagoodage. A plastron 
before me of this species was discovered in Sharon, Wastenaw county, 
Michigan, in 1838, ‘by Dr. C. B. Porter, who inscribed the date and his 
name upon it. The animal was again discovered within half a mile of 
same spotin 1868 The size of the letters and figures show that the plastron 
could not have grown perceptibly during this period of thirty years. 
From this and other cases where people have inscribed their names and 
dates upon them, we may safely conclude that some, if not ali, of our 
land and fresh water turtles wander to but a short distance, grow slowly, 
if at all, after attaining a length, in this species, of eight inches. In the 
case of Cistudo clausa, sixty years elapsed between the time of the in- 
scription and its rediscovery, and it then, as in this species, was found 
within half a mile of the place where it was originally marked. 
FAMILY CINOSTERNIDA. THE CINOSTERNOID 
TURTLES. 
Feet palmate; toes four or five, fingers five; carapax high, narrow and composed of 
hard osseous plates; plastron small, between cruciform and elliptical, with only seven, 
nine or eleven shields; marginal plates twenty-three, vertebrals five, narrow, becoming 
broader posteriorly ; costals large, fonr on each side; margins of carapax turning down- 
ward and inward instead of outward; head pointed ; sockets of eyes deep. 
+ Plastron oval with movable hinge between the pectoral and preanal plates, allowing 
it to close the shell. 9 A : : ; : : .  CINOSTERNUM. 
¢ Plastron craciform; no movable hinge behind; incapable of closing the shell. 
AROMOCHELYS. 
GENUS CINOSTERNUM. Spix. 
Head sub-quadrangular, pyramidal and broad; superior maxillaries rather widely 
separated behind ; jaws slightly hooked with an inframental papilla; cranium with a 
single rhomboidal plate; plastron oval; pectoral and preanal plates articulated by a 
movable suture allowing the animal to close the shell; vertebral plates somewhat im- 
bricate; tail long, and unguiculate in the males. 
CINOSTERNUM PENNSYLVANICUM Bosc. 
Mud Wortoise. 
Testudo pennsylvanica, GMELIN, SCH@PFF, LATREILLE, SHAW, DAUDIN, EDWARDS. 
Emys pennsylvanica, SCHWEIGGER, IIARLAN. 
Terrapene pennsylvanica, MERREM, SCHINZ. 
Cistudo pennsylvanica, Say. 
