Abstract
AT the last meeting of the Connecticut Assembly, February 17, Prof. O. C. Marsh made a communication on a new order of Eocene Mammals, for which he pioposed the name Tillodontia. These animals are among the most remarkable yet discovered in American strata, and seem to combine characters of several distinct groups, viz., Carnivores, Ungulates, and Rodents. In Tillotherium, Marsh, the type of the order, the skull has the same general form as in the bears, but in its structure resembles that of Ungulates. The molar teeth are of the ungulate type, the canines are small, and in each jaw there is a pair of large scalpriform incisors faced with enamel, and growing from persistent pulps, as in Rodents. The adult dentition is as follows:— Incisors (2/2; canines (1/1; premolars (3/2; molars (3/3. The articulation of the lower jaw with the skull corresponds to that in Ungulates. The posterior nares open behind the last upper molars. The brain was small, and somewhat convoluted. The skeleton most resembles that of Carnivores, especially the Ursidœ, but the scaphoid and lunar bones are not united, and there is a third trochanter on the femur. The radius and ulna, and the tibia and fibula are distinct. The feet are plantigrade, and each had five digits, all terminated with long, compressed and pointed, ungual phalanges, somewhat similar to those in the bears. The other genera of this order are less known, but all apparently had the same general characters. There are two distinct families, Tillotheridœ, in which the large incisors grew from persistent pulps, while the molars have roots; and the Stylinodontidœ, in which all the teeth are rootless. Some of the animals of this group were as large as a Tapir. With Hyrax or the Toxodontia the present order appears to have no near affinities.
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New Order of Eocene Mammals . Nature 11, 368 (1875). https://doi.org/10.1038/011368b0
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DOI: https://doi.org/10.1038/011368b0