ART. 5. A NEW FOSSIL TURTLE—GILMORE, 3 
part of the carapace less completely than in the female, specimen 
No. 10462, U.S.N.M. (See pls. 2 and 4.) With the exception of the 
considerable difference in size of the two these are exactly the differ- 
ences to be observed between the sexes of K. flavescens, as is shown 
by specimens Cat. Nos. 22671 and 19058, U.S.N.M. 
While there are other characters, to be pointed out later, which 
indicate the affinities of A. arizonense to be nearest to K. flavescens, 
the sudden enlargement of the marginal scutes beginning with the 
ninth, see figs. 3 and 4, which arises well above the middle of the eighth 
peripheral, whereas the superior terminations of those anterior barely 
reach the middle and are usually 
below, are precisely the conditions 
found in K. flavescens, a character 
which Doctor Stejneger assures me 
is constant for that species, and 
one which serves to distinctly sep- 
arate it from all other members of 
the genus. 
In outline the carapace of K. 
arizonense is broadly oval, slightly 
excavated above the neck (see fig. 
2), the hinder end evenly rounded 
with a slight median V-shaped 
notch. The length of the carapace 
of the paratype in a straight line is 
148 millimeters. It is estimated 
that the carapace of the type which 
lacks some of the median anterior 
margin; would slightly exceed 170 FIG. 2, CARAPACE OF KINOSTERNON ARIZONENSE, 
millimeters in length. In width — No. 10462, U.s.N.M. ParatyPE. FEMALE. 
the type measures Wis) millimeters; ©. 2, ©: 8) cosean pones |) ANp's; Nj 1, 2354 
ane 5, 6, NEURAL BONES 1 TO 6; NU, NUCHALBONE; 
the paratype 108 millimeters; PER 10, TENTH PERIPHERAL BONE; PY, PYGAL 
height at the center, type 73 milli- BONE; SPY, SUPRAPYGAL BONE; V1, V5, VERTE- - 
“"—aW BRAL SCUTES 1 TO 5. ONE-HALF NATURAL SIZE. 
meters, paratype 47.5 millimeters. 
The surfaces of the shell are smooth, there being no indications of 
ridges or carinae, such as are found in some of the living species of 
the genus. The sulci are narrow and well impressed. The bone of 
both carapace and plastron is relatively thin. The free margins of 
the peripherals present a sharp edge, those posterior to the inguinal 
notch having a tendency to flare upward. 
The paratype (pl. 3) shows the presence of a good sized nuchal 
slightly excavated for the neck on the free border, which measures 
21 millimeters wide; the greatest width of this bone is 36 millimeters. 
It cannot be determined from the present specimens whether the 
nuchal was in contact with the first neural or whether these elements 
