2.02 FOSSIL TURTLES OF NORTH AMERICA. 
The humerus (fig. 269) resembles that of a true sea-turtle. The total length is toomm. The 
distal end is broad and flat. The head of the bone is elongated reniform, the long axis being 
at nearly right angles with the plane of the distal end. Its long diameter is 32 mm.; the 
shorter, 17mm. The ulnar process is broken away, 
but a groove separated it distinctly from the head. 
The radial process is divided into two portions; one 
part being on the under side of the shaft, 40 mm. 
below the upper border of the head; the other part 
on the radial border, still further down on the shaft. 
Both portions are prominent. The narrowest part 
of the shaft is 20 mm. wide and 11 mm. thick. The 
distal end is 41 mm. wide. The ectepicondylar pas- 
sage is a foramen. It emerges on the lower side 
of the bone 10 mm. above the distal extremity. 
The condyles are distinctly separated from the sur- 
rounding bone. Their fore-and-aft extent is 22 mm. 
The radial epicondyle is broad, thick, and flat; the 
ulnar little prominent. It is remarkable that Cope 
in his description of this bone regarded the anterior 
border as the posterior. 
Genus LEMBONAX Cope. 
Fic. 269. —8 yllomus cris patus. Right . Plastron with probably 2 fontanel extending 
humerus. Type. >3. from the entoplastron to the xiphiplastra. No 
digitations of bone proceeding from the plastral 
bones toward the midline. Epiplastra firmly sutured 
to the hyoplastra, the suture oblique to the midline; the xiphiplastra similarly joined to the 
hypoplastra, the suture at right angles with the midline. 
Type: Lembonax polemicus Cope. 
On left, the ventral surface; on right, the radial border. 
The position of this genus is very problematical. Cope concluded originally that the 
relationships were with the Chelydride rather than with the Cheloniidz. At a later time he 
stated (Amer. Naturalist, xvi, 1882, p. 989) that not enough was yet known to assure us to 
what family the genus belonged, except that they were not “Trionychide. Nothing has been 
added to our knowledge on that point since that time. Cope referred two addigonal species, 
L. propyleus and L. isulariss to the genus. While the present writer retains these species 
in this genus provisionally, there appears to be no evidence whatever that they belong there. 
Ror want of knowledge where Lembonax polemicus belongs it is here referred to the 
Cheloniide. 
Lembonax polemicus Cope. 
Fig. 270. 
Lembonax polemicus, Corr, Ext. Batrach., Reptilia, Aves N. A., 1870, p. 168.—Hay, Bibliog. and 
Cat. Foss. Vert. N. A., 1902, p. 444. 
This species was sent to Professor Cope from the Eocene greensand near Farmingdale, 
Monmouth County, New Jersey. The type and only known specimen is now in the Agiencan 
Museum of Natural History and bears the number 1134. It furnishes a portion of the plastron 
and the base of the scapula. The materials indicate a large individual, but they furnish 
meager information regarding its structure and relationships. 
The most important parts of the plastron are a portion of the right hyoplastron and a 
portion of the right hypoplastron. The outer borders of both these bones are wanting. 
The hyoplastral fragment (fig. 270) has at present a length of 233 mm., having apparently 
lost a slight portion since it was studied by Cope. The greatest width is 136 mm. The thick- 
ness varies from 10 to 15 mm. Anteriorly the bone terminates at the union with the epi- 
plastron. Posteriorly, there is no indication of suture with the hypoplastron, and this may 
have been farther away than indicated in the figure. The inner border of the bone is thick, 
