DERMATEMYDID&. 275 
shown in the figure. His fig. 4 represents the second left peripheral. Fig. 8 is from a portion 
of the left first costal and its median notch fits accurately on the upper border of the original of 
his fig. 4. Cope’s fig. 6 is almost certainly that of the right third peripheral. In the collection 
there are present the left second and third peripherals of another individual. These bones cer- 
tainly do not belong to any species of Baéna. They closely resemble those of Baptemys wyo- 
mingensis, and in all probability belong to that species. : F 
Cope’s assignment of these bones to Baéna was determined by the bone represented by 
his fig. 3. It is indeed very peculiar. Fig. 345 represents a section. Cope regarded it as form- 
Fics. 342~345.—Baptemys wyomingensts. Pelvis, scapula and peripheral. 
342- Pelvis, from left side. 3. No. 5934 A. M.N.H. fl, ilium; isch, ischium; pub, pubis. 
343- Pelvis of individual of fig. 342. Seen from below. 3. il, ilium; isch, ischium; pub, pubis. The suture 
between the right and left pubes ran from a point 2 mm. on the left of the leader from pub backward to 
a point 2 mm. on the left of the line of two short dashes. 
344. Scapula. 3. Specimen in U.S.N.M. 
345. Section of peripheral described by Cope as that of Baéna ponderosa. X34. 
ing a part of the hinder border of the carapace, the scute seen on it being the hindermost 
one. However, the writer has found in the collection another fragment which continues the 
border 5 or 6 mm. toward the left, and on it begins another marginal scute. It is the writer’s 
conclusion that this bone also belongs to Baptemys and is a malformed portion of the hinder 
border of the carapace. 
Baptemys tricarinata sp. nov. 
Figs. 346-349. 
Dermatemys——, Cope, Bull. U. S. Geol. and Geog. Surv. Terrs., v1, 1881, p. 184. 
Remains belonging to 2 individuals of the present species were collected in the Wind 
River deposits, during the summer of 1905, by the expedition in charge of Mr. Walter Granger, 
of the American Museum of Natural History. One of these, No. 6109, was found at the 
mouth of Alkali Creek, Fremont County, Wyoming; the other, No. 6110, on the divide 
between Alkali and Poison Creeks. No.6109 is made the type of the species. Both specimens 
are considerably fractured, neither of them furnishing a complete carapace. Taken together, 
however, the two specimens give practically the whole structure of the shell. The species is 
distinguisht from B. wyomingensis by the possession of three dorsal carina and a pointed 
hinder plastral lobe. 
The carapace of No. 6109 (fig. 346) has an approximate length of 460 mm.; a width of 
about 330 mm. Its structure differs only in minor points from that of B. wyomingensis. The 
neurals are long and narrow. The peripherals differ little from those of the Bridger species, 
