. Contributions to Canadian palæontology. Paleontology. Nasals and horns of Megacerops syceras, fig. 9 viewed from above, fig. 10 from the front, fig. 11 from the right side. One- fourth the natural size; figs. 10 and 11, after Cope. Megacerops primitivus, Sp. nov. Plate VI, figs. 4 and 5. la 1904 the writer was fortunate in securing, from the Oligoeene deposits of the Cypress hill9, a mandible of a Titanothere that is of considerable interest. It is the most perfect lower jaw obtained so far from this locality, and is the type of the above named species. The specimen consists of both halves o
. Contributions to Canadian palæontology. Paleontology. Nasals and horns of Megacerops syceras, fig. 9 viewed from above, fig. 10 from the front, fig. 11 from the right side. One- fourth the natural size; figs. 10 and 11, after Cope. Megacerops primitivus, Sp. nov. Plate VI, figs. 4 and 5. la 1904 the writer was fortunate in securing, from the Oligoeene deposits of the Cypress hill9, a mandible of a Titanothere that is of considerable interest. It is the most perfect lower jaw obtained so far from this locality, and is the type of the above named species. The specimen consists of both halves of the jaw. The left ramus is perfect, with the full number of teeth preserved ; the right ramus lacks the fourth premolar, and the molars, with that part of the alveolar border that held these teeth. The mandible is of fair size, and belonged to an adult individual. It presents the follow- ing dental formula : I3, Of, P4, Mj. There is a diastema behind the canine, a character which, taken in conjunction with the presence of three incisors and four premolars, is indicative of a somewhat primitive species. The chief characters displayed are : incisors, in three pairs,with a space between the inner pair; canines, of small diameter, apparently short; a diastema between the canine atid the first premolar; first premolar, small; third premolar, becoming molariform, fourth premolar, molariform; symphysis, long ; symphysial surface between canines, narrow; jaw contracted at the diastema; external cingula, moderately developed; internal cingula, wanting ; mental foramen, beneath the second premolar; coronoid process, short. Megacerops avus (Marsh), from the Oligoeene of South Dakota, has three pairs of inferior incisors but only three premolars below on each side, and there is a short diastema behind the lower canine. Its dimensions are greater than those of M. primitivus. These two species are apparently the only ones of the Oligoeene Titanotheres in which there are three pairs of inc
Size: 1398px × 1788px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1880, booksubjectpaleontology, bookyea
