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Show 69 of the beam with a basal protuberance of the frontal bone by a btirr. These observations have been made on the American species by myself, and published in the report on the Vertebrate Fossils obtained in New Mexico, ( see Annual Report Chief of Engineers, 1874, p. 604.) The specimens obtained by the expedition prove that three, perhaps four, species of this genus occur in the Santa re* marls, one of which had been previously found by myself in the Lonp Fork beds of Colorado and another in the corresponding formations in Nebraska by Dr. Hay den. To the latter the name of Meryoodis necatus was applied by Dr. Leidy in 1854 and Cervu* Warrenii in 1858. The former was represented oy mandibles with dentition; the latter by horns. The discovery of crania with horns and teeth enables me to unite these supposed species. A third species, discovered by Dr. Hayden in Nebraska, was named by Dr. Leidy Cosoryx furoatus in 1869. In commenting on this species, Professor Gervais remarks ( Journal de Zoologie) that the genus Cosoryx is not distinct from Dkrocerus, a statement confirmed by the comparison with the figures of the D. dichotomus, Gerv., from the French Miocene. I described an allied epecies, D. ramosus, from the Santa Fe* marls. Finally, a species considerably larger than any of the preceding was described by me nuder the name of Cosoryx teres. The D. gemmi/ er is distinguished from the other species of the Santa Y6 marls by its materially smaller size. Dicrocerus necatus, Leidy.- Merycodon necatus, Leidy, Proceedings Academy Phi lad el - £ hia, 1854, 90; Extinct Mammalia Dakota and Nebraska, 162.- Cervus Warrenii, > eidy, Proceedings Philadelphia Academy, 1858, 23; Extinct Mammalia Dakota and Nebraska, 172. Abundant in the Santa Fe* marls. Dicrocerus ramosus, Cope.- Cosoryx ramosus, Cope, Report on Vertebrate Fossils, New Mexico, Annual Report Chief of Engineers, 1874, p. 604. Abundant. Dicroceerus teres, Cope- Cosoryx teres, Cope, Report, I. c, 6C5. PHauchenia Humphresiana, Cope, gen. et sp. nov. Char, gen,- Represented in the collection of the expedition by a left mandibular ramus, which includes alveoli of all the teeth, and greater or less portions of all the molars, except the last, and the first premolar. In the specimen, the dental formula is I. f 3 ; C. 1; Pm. 3; M. 4; or one premolar less than in Procamelus, and two more than in A uchenia. On this ground, the present animal is regarded as representing a new genus of Camelidte intermediate between the genera named. A portion of the left maxillary bone of a larger species is thought to belong to the same genus, although it presents the number of premolars found in Procamelus, viz, four. The first and second are, however, very close together, so as to leave about the same relative interval between the first and third, as is seen in the P. Humphresiana, should the second premolar be omitted. The latter tooth is wanting from the lower jaw of the P. Humphresiana, The difference in dental formula between the superior and inferior dental series admitted provisionally in PHauchenia finds justification in the formula of the llamas ( Auchenia) where the premolars are f. Char, specif.- The animal now described is of about the size of the Procamelus occi-dentalis, or somewhat larger than any of the existing llamas. The mandible is stout and deep, contracting rapidly forward. The canine and first premolar are especially stout, and separated by a very short diastema; that separating the first and third premolars is also short, being less thau that which separatee the first and second in Procamelus occidentalis. Could it be supposed that the second premolar is abnormally absent from the P. Humphresiana, the diastema would be reduced to a very small compass. Without this supposition, the diastemata, both before and behind the first premolar, are shorter than in any of the Procameli, as P. robustus, P. angustidens, P. keterodontus, and P. gracilis. The mental foramen issues below the anterior border of the first or canini-form premolar, and the anterior border of the latter marks the posterior margin of the symphyseal suture. The third premolar is nearly as long as, but narrower than, the fourth, and the true molars increase rapidly in size posteriorly. Measurements. M. Length of dental series from front of canine to front of last molar 125 Length from canine to first premolar 010 Long diameter of first premolar 010 Diastema to third premolar 022 Length of third premolar 011 Length of first true molar 019 Width of crown of first true molar 011 Length of crown of second true molar 025 |