132 FOSSIL TURTLES OF NORTH AMERICA. 
Osteopygis gibbi Wieland. 
Plate 26, fig. 1; plate 27, figs. 1, 2; text-figs. 142-146. 
Osteopygts gtbb1, WIELAND, Amer. Jour. Sci. (4), XVII, 1904, p. 118, plates v—vill and text-figs. 3-7. 
The type of this species is No. 783 of the Marsh collection of Yale University. It was 
obtained from the upper bed of Cretaceous greensand, at Barnesboro, Gloucester County, 
New Jersey, in 1870. It was originally studied by Dr. George Baur (Zool. Anzeiger, xu, 
1889, p. 42), who determined from it that Cope had been in error when he stated that the 
genus Osteopygis possest 10 pairs of costal plates. Fig. 1, plate 26, is reproduced from a 
drawing prepared under Baur’s direc- 
tions and shows the nuchal, the periph- 
erals, and the pygal as seen from below. 
In 1904 the specimen was fully prepared 
and the parts put together under the 
direction of Dr. Wieland. A number of 
the figures made by Dr. Wieland are 
here reproduced. 
The specimen is the most complete 
that is known of any species of the family 
and it serves to give us a clear idea of 
the form and the constituents of the 
shell. It will be observed that the out- 
line of the carapace as restored by Dr. 
Baur (plate 26, fg. 1) differs from that 
as restored by Wieland (text-fig. 142). 
Since, however, Dr. Wieland fitted the 
costals to one another and to the periph- 
erals, and brought the plastron into 
relation with the carapace, which Baur 
did not do, itis quite certain that the 
later restoration is the more accurate 
one. It can hardly be wrong except in 
small details. Fig. 143 shows the shell 
from the side. 
In form the carapace is elongated 
Fic. 142.—Osteopygis gibbi. Carapace of type. X#. oval, rounded in front and somewhat 
; ; ; pointed behind. It is somewhat deprest 
c. 8. 1, first costal bone; m. s. 12, twelfth marginal scute; 1.1, : : ES 
first neural; 7.8, eighth neural; 2u.p,nuchal bone; »xz.s, nuchal and especially the hinder peripherals look 
scute; py, pygals spy.1, spy.2, spy.3, suprapygals. more upward than outward. The length 
ina straight line is given as 690mm.; the 
extreme width, as about 580 mm. The nuchal bone is 127 mm. wide in front and has a maximum 
widthof145 mm. Its length is75mm. The dimensions of the neural bonesare shown in the table. 
The eighth neural is apparently followed by a small first suprapygal. ‘This is succeeded 
by an irregularly shaped second suprapygal, 60 mm. long and 162 mm. wide. Behind this 
comes the posterior suprapygal, which has a length of 60 mm, and a width of 97 mm. 
All the peripherals are suturally articulated with the contiguous ends of costal bones, except 
the eleventh, which articulates with the suprapygals The peripherals, except the first, second, 
Neural. Length. Width. 
1 95 41 
2 65 47 
3 65 47 
4 65 43 
5 504 37 
6 45+ 33 
e 45+ 30 << 
8 65+ 384 
Fic. 143.—Osteopygis gibbt. Shell from left side. 4. 
