flat, rugose ossicles, on the sides of the functional third and fourth metacarpals. Metacarpal II was apparently free, as there is a distinct facet on the outer posterior corner of metacarpal III contiguous to, but beneath, the trapezoid facet. Metacarpal V, on the other hand, is represented by a small rugose knob thoroughly coalesced with metacarpal IV. Herein, as with the cervicals, the form under consideration is simply more primitive than is Oxydactylus. No mention of these details is made by Wortman, who merely figures the anterior metapodials and records their length. There is no trace of coössification of the metacarpals, but their flat, somewhat rugose surfaces were closely applied.

The phalanges again are comparable to those of Oxydactylus, the ungual being compressed and deer-like.

Specimen No. 10884, Y. P. M., is distinct from either Paratylopus sternbergi or cameloides, chiefly by its larger size, the robustness of the caniniform teeth, and the length of diastema between I3 and C1. It is not clear, however,

that it is distinct from the paratypes of the cameloides description, especially the upper dentition (No. 7915, A. M. N. H.). It seems fitting, therefore, to name it in honor of Doctor Jacob L. Wortman, the describer of P. cameloides, who for a time rendered so eminent a service to the science of vertebrate paleontology.

Peterson, speaking of Oxydactylus, says this phylum appears to be divergent from that of the true camels and that we are at present able to trace it with some certainty to the genus Protomeryx of the Upper Oligocene. Matthew, however, restricts the use of the term Protomeryx to the two species P. halli Leidy and P. campester Matthew, and uses the new subgeneric term Paratylopus to include what were originally described as Gomphotherium sternbergi (Cope) and G. cameloides Wortman, together with his new species primavus, which he makes the type of Paratylopus. His derivation of Oxydactylus is from Paratylopus through Miolabis, the restricted Protomeryx being in the direct line of camel evolution and leading to Protolabis and Procamelus. As Peterson considers Protomeryx to be a synonym for Gomphoides (preoccupied), it is probable that he and Matthew are referring to the same group under different names, and hence their statements agree. The Yale material thus briefly described certainly bears this out, as it differs from the later Oxydactylus mainly in its greater primitiveness.

4

3 O. A. Peterson, Ann. Carnegie Mus., 2, 472, 1904.

W. D. Matthew, Bull. Amer. Mus. Nat. Hist., vol. 20, 211-215, 1904.

ART. XXVII.-Leptauchenia Leidy and Cyclopidius (Pithecistes) Cope, with descriptions of new and little known forms in the Marsh Collection; by MALCOLM RUTHERFORD THORPE.

[Contributions from the Othniel Charles Marsh Publication Fund, Peabody Museum, Yale University, New Haven, Conn.]

The genera Leptauchenia and Cyclopidius are the most peculiar of all the Oreodontida. Pithecistes Cope is considered identical with Cyclopidius. The first genus is fairly well known, the whole skeleton of L. decora having been mounted, but not as yet fully described. Cyclopidius is known only from skulls and jaws.

Leptauchenia decora was apparently the most numerous, judging from the number of individuals represented in the Marsh and other collections.

The taxonomy of these genera will be discussed in a later paper where the Oreodontidæ as a family are considered. It is sufficient to remark here that they represent the climax of at least a part of this family, which began in the Eocene, reached its greatest development in the Oligocene, and became extinct through these and other highly specialized and peculiar forms in the Miocene or early Pliocene. Leptauchenia represents an earlier geologic epoch than does Cyclopidius (Pithecistes), the latter also showing more marked peculiarities.

The material in the Yale Museum serves admirably to amplify our knowledge of these genera, both in the description of referred specimens and of new species. The excellent illustrations were made by R. Weber.

DESCRIPTION OF SPECIES.

Leptauchenia decora Leidy 1856.

This species is represented in the Marsh Collection by more than forty individuals. Apparently the elements of the skull which were most resistant to destruction were the rami and maxilla with molars. Specimens of this species have been found on the North Platte River, at Crow Buttes, Fort Mitchell, Lawrence's Fork, Court House Rock, Scott's Bluff, Omaha Creek, Rattlesnake Butte (near Chadron), and many from Pumpkin Creekall in Nebraska; and one specimen from Spring Creek, near Camp Baker, Montana, collected by Edward S. Dana and George Bird Grinnell. The description is taken from various individuals, but especially from Cat. Nos. 10119 and 10121.

Specific Characters.-The skull is somewhat smaller than that of Oreodon gracilis, and broader, shorter, and lower. The lacrymal fossa is small and shallow, and the infra-orbital foramen is above the middle of P3. The malar is remarkably robust. The bullæ are much inflated and oval in outline. The palate is nearly flat, while the palatonarial border is opposite the posterior margin of M3. The orbits are large, oval-shaped antero-posteriorly, and look chiefly outward; the facial vacuities are large and extend somewhat posterior to the anterior orbital border; the ramus is similar to that of Oreodon, except that the posterior area is of greater proportionate width and depth; the masseteric fossa is large and relatively deep; the inferior border is straight; the auditory meatus is large, situated a little in advance of and well above the line of the occipital condyles; the paramastoids are plate-like, are in contact with the bullæ, and extend downward but slightly below the inferior border of the bullæ. The dentition shows the full number of teeth common to Oreodon, that is, forty-four. Both molarpremolar series are crowded and the latter somewhat reduced. The molars are more nearly uniform in size reduction from M3 to M1. These teeth are very hypsodont and the external styles are very well developed.

Measurements.

(Cat. No. 10121, Y. P. M., unless otherwise indicated.)

Skull, length, occip. condyle to canine inc., approx.

mm. 107

17-20

Inferior molar series, length (Cat. No. 12668)

32

Superior premolar series, length (Cat. No. 10120)

Inferior premolar series, with P1, length (Cat. No. 12668) 20.5

Leptauchenia cf. decora Leidy.

A skull with jaws attached, not readily identifiable with any of the three described species of this genus, was collected in 1914 by John T. Doneghy, Jr., at Rattlesnake Butte, about 6 miles southwest of Chadron, Nebraska. This skull is that of an immature individual, in which neither superior nor inferior third molar is erupted. It was found in the Lower Miocene beds, and I believe represents a form intermediate in size between L. decora and L. major.

This specimen, Cat. No. 12221, Y. P. M., is exceedingly well preserved, with the exception of the superior part of the muzzle in advance of the orbits, including the superior incisor border. The chief characters may be set forth briefly. The total length of the skull is approximately that of L. decora, but in the fully adult form it must have been somewhat longer. The sagittal crest is short and has a nearly straight contour. From the junction of the temporal ridges, the upper contour descends steeply to the tip of the nasals, giving an anthropoid appearance from a lateral view. The orbits are small and look chiefly upward and outward, in which