226 FOSSIL TURTLES OF NORTH AMERICA. 
Key to THE AMERICAN GENERA OF FossiL DERMATEMYDIDA. 
A. Upper Cretaceous genera. 
a’. No inframarginals, coarsely sculptured with pits, furrows and pyramidal elevations Basilemys 
a2. culpturestine and, pranullater accep ei ee eee eet eee teers Compsemys 
a*, Sculpture consisting of shallow pits. Borders of carapace acute-edged. Plastron 
rounded in front and behind, with full set of plastral scutes. Hinder marginal 
scutes srisine welllon itheicostalabones meat. «rites eee ee Adocus 
a’, Like Adocus, but with axillary and inguinal buttresses and costals sending long 
rib-heads/intoithe peripheralss, Bonesithimy ecient terete siesta tear Zygoramma 
a’. Shell thick and heavy; the free borders of carapace thick and obtuse. Hinder 
marginal scutes rising little or not at all on thecostalibonessee aera ..... Agomphus 
® Vertebral es said to b lly ver th i 1 bones H hi 
a®. Vertebral scutes said to be usually narrower than the neural bones... .. .........Homorophus 
AA. Tertiary genera. 
a‘. Like Adocus, but hinder marginal scutes not rising on costal bones. Torrejon... d/amosemys 
a’. See 4. a® above. Hinder lobe of plastron pointed. Midway................... Agomphus 
a®. Shell thick; free borders acute; three ridges along back; the plastron rather loosely 
joined to carapace. No inguinal buttresses. Torrejon...................... Hoplochelys 
a‘, Like Hoplochelys, but without inguinal buttresses. Wasatch................. Kallistira 
a’. Not well known. At least the anterior peripherals obtuse. Wasatch.............. Notomorpha 
a®. A full set of neurals. Carapace smooth, with a median carina on rear of cara- 
pace. Plastron sutured to carapace. Wasatch, Wind River, and Bridger.... | Baptemys 
a’. Shell finely sculptured. Plastron much reduced and loosely joined to the carapace. 
ya tbs( reeneeee n Rr an rent on pace Oma tenikas ah onesie” eae .......  Anosteira 
a’. Shell smooth; no buttresses; five pairs plastral scutes. Oligocene.............. Xenochelys 
Genus BASILEMYS Hay. 
Shell highly sculptured. Epiplastra much thickened. Bridge wide. Intergular scutes 
present. Pectorals greatly expanded at the midline, narrowed laterally. An axillary and an 
inguinal scute but no other inframarginals. 
Type: Compsemys variolosus Cope. 
This genus differs from other known genera of Dermatemydide in having no infra- 
marginals, except the axillary and the inguinal. 
Basilemys variolosa (Cope). 
Plate 32, fig. 4; plate 34, fig. 1; text-fig. 287. 
?Compsemys ogmius, Cope, Vert. Cret. Form. West, 1875, pp- 91, 261; Proc. Acad. Nat. Sci. Phila. 
1875, p. 9; Brit. N. A. Bound. Sury., Report on aes and Resources 1875, p. 336. 
Compsemys vartolosus, Cope, Proc. Acad. ‘Nat. Sci. Phila. 1876, p. 2573 Bull. U. S. Geol. Surv. Terrs., 
mt, 1877, p. 573- : lok 
oe us vartolosus, LAMBE, Ottawa Naturalist, xv, 1901, p. 63, plates mi—vi; Cont. Canad. Palzont., 
I (4to), p. 39, plate u, text-figs. 4-6. 
ie. vartolosus, Hay, Bibliog. and Cat. Foss. Vert. N. A., 1902, p- 445. 
Adocus (Basilemys) variolosus, OsBorn, Cont. Canad. Palzont., 111 (4to), 1902, pp. 12, 16. 
Basilemys ogmtus, HatcuHeR, Bull. U. S. Geol. Surv. No. 257, 1905, p. 76. 
The type of the present species consists of nearly the whole of the plastron, various periph- 
eral bones, and two imperfect costal plates. These are now in the American Museum of 
Natural History, and bear the catalog number 1465. This type, with fragments of other 
individuals, was collected for Professor Cope, in 1876, by Mr. Charles H. Sternberg, in the 
Judith River beds of Montana. Since that time arker specimens of the species have been 
collected by members of the Geological Survey of Canada, in Judith River deposits, just 
north of the United States boundary line and east of the Rocky Mountain range. More 
accurately, the remains were taken on Mackay Creek, along Old Man River, and on Red 
Deer River. 
Fig. 287 is reproduced mostly from Cope’s type, but it is probable that the fragment of 
bone around the axillary notch and the piece of epiplastron do not belong to the same indi- 
vidual as the remainder of the specimen, these anterior pieces being somewhat larger than we 
