BAENID. 87 
pedicels of the quadrates. There appears to have been only a rudimentary ridge on the 
triturating surface. The sutures between most of the bones may be traced, but those separating 
the frontals from the parietals have not been observed. Nasals were quite certainly present, but 
they are broken away. The lower jaw is present (fig. 75). The triturating surface is trans- 
versely concave and g mm. wide. The tip of the jaw is damaged so that the length of the 
symphysis can not be exactly determined; but it was not far from 15 mm. 
Chisternon hebraicum Cope. 
Plate 21, figs. 3, 4; plate 23, fig. 15 text-figs. 76-87. 
Baéna hebraica, Corr, Paleont. Bull. No. 1, 1872, p- 463; Proc. Amer. Philos. Soc., x11, 1872, p- 4635 
6th Ann. Report, U.S. Geol. Surv. Terrs., 1872 (1873), p- 62; Vert. Tert. Form. West, 1884, p. 146, 
plate xix, figs. I, 2.—Hay, Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 438. 
Baéna undata, Hay, Bull. Amer. Mus. Nat. Hist., XX1, 1995, P- 138, figs. 1-3. 
Professor Cope’s type of the present species consists of about two-thirds of the anterior 
portion of the carapace and the plastron. It was obtained by him in the Bridger Badlands 
along Cottonwood Creek, Wyoming, and hence in the level known as B. This type is now in the 
U.S. National Museum at Washington. It appears to be necessary to correct some of Cope’s 
measurements. The transverse axial width 
is given by him as 500 mm., but it is only 
Nu Dp 
Le Spren XP oN 420mm. Accordingly, Cope’s figures are 
a aa RS ; just one-third the size of nature. Cope’s 
Dea o nay \ estimate of the length was also 500 mm., 
j Cpe aah OE dims We BS but the writer would make it only about 425 
SN ‘ mm. In either case the shell is about as 
{ \ broad as long. The length of the anterior 
i aa, ‘ lobe of the plastron, to a line joining the 
i . _\ bottoms of the axillary notches, is 125 mm. 
- Its width is 147mm. The bridges are 162 
ae : mm. wide. The hinder lobe has a basal 
width of 160 mm. 
As shown by Cope’s figures, the nuchal 
we } i ~ and the anterior marginal scutes have small 
ee extent at right angles with the free border, 
i ee and the first vertebral is transversely divided 
so as to make 6 vertebrals in all. Themargi- 
Fic. 76.—Chisternon hebratcum. Portion of carapace. nals over the bridges are higher than long, 
x4. No. 5961 A. M. N. H. and the corresponding costal scutes become 
thereby about as high as long. There is 
likewise a supernumerary costal scute on 
each side of the first vertebral. 
The shoulder-girdle is present, but has not been wholly freed from the matrix. The 
scapula is at least 90 mm. long from the glenoid fossa to the upper end. At its base the cora- 
coid has a diameter of 7 mm.; ata distance of 65 mm. from the glenoid fossa the diameter 1s 
65 mm. 
No. 5961 of the American Museum is referred to this species. It was collected in 1903 by 
Mr. L. S. Quackenbush, a member of the museum’s party. The locality is Grizzly Buttes, 
not far from the locality where Cope’s type was collected. It was found lying in close prox- 
imity with the specimen numbered 5962 and referred to Leidy’s Chisternon undatum. Both 
specimens furnisht good skulls and other skeletal parts. Figure 76 represents the carapace 
of No. 5961; fig. 77, the plastron. The shell, especially in the region of the distal ends of the 
costals, is thin and fragile and some parts were lost. The right half of the nuchal is gone, the 
rear of the carapace is missing. 
The axial length of the carapace was close to 474 mm.; the greatest width 435 mm. It was 
moderately convex. The surface 1s nearly smooth. Along the areas of the vertebral scutes 
are some traces of the sculpture so conspicuous 1n the case of species of Baéna. Across some ot 
cu pPat; front costal plate; c.s. 1, first costal scute; .1, 7.2, 
neural bones; pren, preneural. 
