A new order of extinct Eocene mammals (Mesodactyla) / by O.C. Marsh.

  • Marsh, Othniel Charles, 1831-1899.
Date:
[1892]
Catalogue details

Licence: Public Domain Mark

Credit: A new order of extinct Eocene mammals (Mesodactyla) / by O.C. Marsh. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    [Prom the Ameeio. F Science, Vol. XLIIl, May, 1892.] A New Order o' %^lEdcene Mammals {Mesodactyla); ry^O. Q. Maesh. DuEiNG explorations in tlie lower Eocene deposits of Jfew Mexico, carried on by the writer in 1876-1880, some of the first fossils discovered were remains of small mammal* about as large as a fox, and of much scientific interest. The teeth are somewhat similar to those of Ungulates, but the rest of the skeleton, and especially the limbs and feet, are of a generalized type quite distinct from any of hoofed animals known, recent or extinct. Some parts of the structure seem to indicate an affinity with Eyrax, but the limbs and feet show characters resembling those of the Primates, especially the extinct forms, and likewise seen in Insectivores, and even in some of the Eodents. A large collection of these remains was secured, and when examined was found to include several distinct forms, all of small size, and forming together a natural group. One of these forms was de'scribed by Cope, under the name Meiiiscotherium chamense, the type being a portion of an upper jaw, with the molars in place,* This specimen was subsequently described and figured by that author, who regarded it as belonging to the Perissodactyles.f Later, he defined two additional species, and proposed for the family the name Meniscotheriidm ; and more recently has described and figured various parts of the skull and skeleton.;}: Several other authors since then have discussed the affinities of this peculiar family, but mainly without presenting any new facts bearing on the question, the general opinion being that these animals arc primitive forms of Perissodactyla, more or less related to Chalicotherium, Kaup, which genus they resemble in dentition. A comparison of the feet would have been more important, but those of Meniscotherium, at least, were unknown. * Eeport of Chief of Engineers for 1874, pt. ii, p. 596. f Extinct Vertebrata, p. 251, pi. Ixvi, 1877. i Tertiary Vertebrate, 1884.