,312 [December, 



vertebra were discovered by Dr. Hayden in the lowest member of the Lignite 

 formation of Grand River, Nebraslva. The other vertebra was obtained by Capt. 

 Alfred Sully from an Indian, and is presented to the Academy. The specimen 

 Dr. Hayden supposes to have been derived from the same locality. 



The vertebral bodies very much resemble those of the lumbar vertebra? of the 

 elephant in form and size, Ijut they jjossess articular processes of a very distinct 

 character, and one inch in diameter, for chevron bones. Viewed in front, the 

 bodies are quadrately oval in outline and notched above, one of them being 5 

 inches in diameter, the other 4J inches deep and 4} transversely. Their length 

 is about 2| inches ; their anterior face is convex, and their posterior face is con- 

 cave, with a depth of almost half an inch. The transverse processes, broken 

 away, projected from the conjunction of the vertebral arches and bodies. The 

 spinal foramen, retained entire in the smaller specimen, is circular, and one inch 

 in diameter. 



The first phalanx is 5 inches long, 4^ wide at base and 3J thick in the same 

 position; and 4 inches wide and 2 J thick at the distal end. Deep concavities 

 exist each side of the latter for the lateral ligaments. The proximal articula- 

 tion is a transverse reniform concavity ; the distal articulation a transverse con- 

 vexity, slightly concave towards the middle. 



CHELONIA. 



5. CoMPSEMTS viCTUs, Lcidy. 



Founded on a vertebral plate, the greater portion of the fifth costal plate, 

 and a fragment of the last costal plate, from Long Lake, Nebraska. 



The vertebral plate is an inch broad and nearly the same length. The fifth 

 costal plate is 1^- inches wide, and 2 lines thick, and in its perfect condition 

 appears to have been almost 4 inches long. The fragment of a last costal plate 

 is 3 lines thick. 



The marking of the third or fourth vertebral scutes upon the fifth costal plate 

 indicates them to have been about 2 inches in width. 



The free surface of all the bones is thickly studded with granular tubercles, 

 which give to it a shagreened appearance, difierent from anything observed in 

 recent turtles. 



6. Emys obscurus, Leidy. 



Found with the preceding, were the fivagments of a costal plate, which is 16 

 lines wide, l^ lines thick, and when perfect appears to have been almost 5 inches 

 long. Its free surface is smooth. 



7. Trionyx foveatus? Leidy. Proc. A. N. S., VIII. 73. 



Fragments of a last costal plate, of the right side, 4 lines in thickness, were 

 found with the preceding. 



PISCES. 



8. Mylognathus priscus, Leidy. 



Founded on an upper maxillary bone of a small chimseroid fish, found in com- 

 pany Avith the above mentioned remains of turtles, at Long Lake, Nebraska. 

 The bone forms a narrow triangle which, in its perfect condition, appears to 

 have been only a little over an inch in length, and it is 3j lines wide at the 

 2)OSterior part. Two teeth occupy the whole length and breadth of its surface. 

 Their free surface is convex and porous. The posterior one is almost 8 lines 

 long, and the anterior one about 6 lines. 



Descriptions of three new genera; twenty-three new species Middle Tertiary Fossils from 

 California, and one from Texas. 



By T. A. Conrad. 



JANIRA, Shum. 



Janira hella. Subtriangular ; inferior valve convex, ribs 14 or 15, square, 

 about as wide as the intervening spaces, very prominent, some of them with 



