Part 7

The neural canal is very wide and depressed in the first, but decreases rapidly backwards, becoming extremely small in the last.

_Caudal region_ (Plate VI., Fig. 6).--(Description based upon the first four.)

The centra of the caudal vertebræ are rather long, narrow, and greatly depressed in the middle; they decrease in size gradually backward. The pedicles and laminæ are short and thin, enclosing a small neural canal. The neural spines point directly back, being almost parallel with the axis of the centrum. They are slender and tuberous at the extremity. The transverse processes are very long, wide, and thin, thickened somewhat at the ends, and project directly out; they decrease in size backwards. From the persistence of the neural canal, and from its comparative size, it would seem as if the tail was considerably larger than that of the elephant.

_Measurements of Vertebræ._

_Cervical region_ (Plate VI., Fig. 11).

M. Diameter of cervical (vertical) ·079 Diameter of cervical (transverse) ·111 Diameter of cervical (fore-and-aft) ·051 Extreme length of prolongation of pedicles for zygapophyses ·089 Long diameter of vertebraterial canal ·040 Width of pedicles ·035

_Dorsal region_ (Plate VI., Figs. 2 and 3).

M. In anterior region: Diameter of centrum (fore-and-aft) ·075 Diameter of centrum (vertical) ·062 Diameter of centrum (transverse) ·142 In posterior region (Plate VI., Fig. 3).: Diameter of last dorsal (vertical) ·087 Diameter of last dorsal (transverse) ·110 Average width throughout the series of neural canal ·097 Width of transverse process (anterior dorsal) (Fig. 2, Plate VI.) ·075 Length of lamina from prezygs. to post-prezygs. (Fig. 2, Plate VI.) ·12 Length of transverse process (middle dorsal). (Fig. 3, Plate VI.) ·055 Vertical length of anterior dorsal from tip of spine to hypapophysial keel ·183 Width between inner margins of metapophyses (last dorsal) ·172

_Lumbar region_--Last lumbar (Plate VI., Figs. 4 and 5).

M. Diameter of centrum (fore-and-aft) ·095 Diameter of posterior face (transverse) ·111 Diameter of posterior face (vertical) ·078 Extreme width between transverse processes ·214 Width between pre-zygapophyses ·110 Length of neural spine from lamina ·060 Vertical length from tip of spine to lower side of centrum ·194

_Sacral region._

M. Length of sacral series ·264 Transverse extent of sacral series ·298 Diameter of first vertebra at free end (transverse) ·109 Diameter of first vertebra at free end (vertical) ·072 Diameter of first vertebra at free end (tore and aft) ·070 Diameter of last vertebra at free end (transverse) ·053 Diameter of last vertebra at free end (vertical) ·031 Diameter of neural canal at first vertebra (transverse) ·100 Diameter of neural canal at last vertebra (vertical) ·018 Long diameter of first transverse foramen (internal side) ·076

_Caudal region_ (Fig. 6, Plate VI.).

M. Length of first four ·252 Diameter of centrum, first (fore-and-aft) ·061 Diameter of neural canal of first (transverse) ·035 Extent of transverse process in first ·085 Extent of transverse process in fourth ·046 Fore-and-aft width of transverse process of first in the middle ·048

_Ribs._--Description based upon two perfect ones, and parts of four more.

The ribs, as in _Dinoceras_, "resemble very much those of the Mastodon." The capitulum has two convex facets, separated by a narrow groove. The sternal end in one is very much expanded, but less so in the other. The tubercle is small, and is situated upon the prolongation of the lamelliform process for the intercostal muscles. The angle is much sharper than in the corresponding ribs of _Mastodon_.

_Measurements of Ribs._

M. Length of rib without curvature ·571 Length of rib with curvature ·739 Width of rib just below head ·049 Width at muscular attachment ·063 Vertical diameter of larger facet of capitulum ·039

_Scapula_ (Plate VIII., Fig. 1).--The scapula is subtriangular, with the pre-scapular border as base, and the apex half way up the postscapular.

On the external side the pre-scapular fossa is concave antero-posteriorly, and plane in the direction of its length; it is very thin in the middle, but becomes heavier at the lateral border. The postscapular fossa is larger and less concave; both fossæ, as they approach the upper border, gain greatly in thickness.

The spine rises from the supra-scapular border, and extends to within an inch from the glenoid cavity. It is decidedly antroverted; thickest and highest near glenoid cavity; thinnest and lowest in the middle, expanding again at its upper extremity; its acromio-scapular notch is long and shallow. The acromion is rudimentary.

The coracoid process is a low, rugose tuberosity; the coraco-scapular notch is short and low.

The internal surface of the scapula has a large, smooth median ridge, extending the whole length of the bone, separating it into slightly concave fossæ. About two thirds up, the median ridge sends obliquely up two branches, forming a V, superimposed upon the main ridge; but these disappear before they reach the upper extremity. The whole inner surface is curved outward, presenting a concave appearance throughout.

The glenoid cavity is deep, ovoid in form, with its greatest diameter fore-and-aft, and its smaller end behind.

The resemblance between the scapula of _Uintatherium_ and that of the _Proboscidea_ is more closely marked than in any other corresponding bones. The chief points of similarity are: first, the subtriangular shape; second, the same relative proportions between the fossæ; third, the antroversion of the spine; fourth, the glenoid cavity looking directly down. The marked points of difference may be summed up as, first, in the dissimilar proportion of the glenoid cavity; second, the great thickening of the spine at its upper and lower extremities; third, in the high, shallow acromio-scapular notch; fourth, in the longitudinal concavity of the internal surface.

_Measurements._

M. Extreme length of scapula ·42 Extreme length of spine ·31 Extreme thickness of spine at upper margin ·098 Extreme height of spine ·109 Basal width of proximal end of spine ·032 Basal width of distal end of spine ·030 Basal width of middle part of spine ·011 Length of glenoid cavity ·149 Width of glenoid cavity ·096

_The Humerus_ (Plate VII., Fig. 1).--The humerus is short, but excessively stout, twisted slightly on its axis; it decreases gradually in size downward, with the smallest diameter about two inches below the end of the deltoid ridge. The head is large, hemispherical, and sessile, projecting very slightly out of the axis of its shaft. The great tuberosity is heavy, but not high, and is separated from the low lesser tuberosity by a shallow bicipital groove.

The trochleæ are very nearly equal in size, directed obliquely to the axis of the shaft, and are separated by a narrow groove, which runs from the supra-trochlear fossa down and in, then back and up to the anconeal fossa. The condylar tuberosities are large and rugose; the external is the greater, and is directed antero-posteriorly. The deltoid ridge is long and heavy, and extends nearly two thirds down the shaft, branching out into two forks near its end. The supinator ridge is short and rudimentary, differing in this respect entirely from the great development found on the humerus of the _Proboscidea_.

The supra-condylar fossa is small, subcircular in form, and very deep, it has the peculiarity of being placed above the external condyle alone. The anconeal fossa is median in position and quite deep.

_Measurements of Humerus._

M. Length ·63 Smallest circumference of shaft just below deltoid ridge ·288 Greatest proximal circumference below greater tuberosities ·45 Width of trochlea on anterior side ·154 Length of anconeal fossa ·071 Width of anconeal fossa ·062 Width of distal end at condylar tuberosities ·23 Length of deltoid ridge ·22 Length of groove running from supra-trochlear to anconeal fossa ·272

_The Ulna_ (Plate VII.. Fig. 2).--The ulna is long, heavy at both ends, with a slender trihedral shaft that curves forward, and decreases in size as it approaches the distal end. The proximal end has its articular face for the humerus divided into three facets, the vertical being long and extremely convex; the horizontal has the pre-axial face the longer. The olecranon is very massive and rugose, sending up on its external side a high, pointed projection; while on the internal side, the olecranon becomes compressed and projects inward; these tuberosities are separated by a wide, shallow groove for the tendon. The distal articular face is large, single, and is concave antero-posteriorly, and convex laterally. The styloid process is very heavy.

_Measurements of Ulna._

M. Length of sigmoid notch ·089 Width of sigmoid notch (horizontal face) ·049 Diameter of proximal end below articular face (fore-and-aft) ·076 Diameter of proximal end below articular face (transverse) ·059 Diameter of distal articular face (fore-and-aft) ·061 Diameter of distal articular face (transverse) ·051 Length of olecranon ·112

_Pelvis._--The _ilia_ are greatly expanded laterally, with the iliac surface concave and the gluteal surface nearly flat; thin in the middle, they increase in thickness near the borders. The crests curve regularly, and project above and beyond the sacrum, but do not bend over the acetabula. The acetabular borders are only slightly concave; the prominence for the attachment of the rectus muscle (extensor) is low and V-shaped. The direct internal surfaces of the ilia, comprised between the pubic and ischiatic borders, become deeply concave below the ischiatic portion of the acetabulum. The sacral surfaces are wide and triangular in shape; above they project beyond the sacral spines.

The ilio-lumbar angle is about 110°. The ischium is, short; a section of it, as it leaves the acetabulum, is subtriangular; but immediately it becomes flattened fore-and-aft throughout its plane of 90° to the axis of ilium; then verging toward the pubic symphysis it becomes small. The tuberosity of the ischium is small and directed up.

The pubis, as it leaves the acetabulum, is sub-cylindrical, after this it is flattened in the same plane with the ischium. The bone as a whole is short, thin, and slightly curved on its own axis; its smallest part makes up the pubic symphysis, which is short. The thyroid foramen is a large oval, with its long diameter parallel to the axis of the ischium.

The acetabulum is large, subcircular, and deep, with prominent borders; especially the iliac, which is produced on its external extremity into a point; the ischiatic is deeply notched. From the wide ligamentous pit in the centre there runs a deep groove part way down the antero-external side of the ischium.

The anterior opening of the pelvis is a wide oval, with its longest diameter transverse.

_Measurements of Pelvis._

M. Transverse diameter of pelvis, including sacrum 1·171 Long diameter of ilium (from lower margin of the crest to sacral surface) ·440 Short diameter of ilium (from acetabulum to upper margin of crest) ·393 Length of acetabular border ·125 Length of ischium ·220 Width of ischium at tuberosity ·124 Length of pubis ·196 Greatest width of pubis ·061 Smallest width of pubis ·027 Long diameter of acetabulum ·139 Short diameter of acetabulum ·118 Long diameter of thyroid foramen ·094

_The Femur_ (Plate VIII., Fig. 4).---The femur is short, with a small oval head, strongly compressed fore-and-aft. It is less out of the axis of shaft than in _Proboscidea_, and has no pit for the ligamentum teres. The shaft is straight and simple, much compressed transversely at the proximal extremity, becoming sub-cylindrical below.

The great trochanter is heavy, rugose, and strongly recurved; it is separated from the shaft by a wide and deep digital fossa. The second trochanter is a mere rudimental tuberosity. The condyles are nearly of an equal size, very convex, and are divided by a deep popliteal groove.

The condylar tuberosities are low, the internal sends obliquely a ridge three inches long, up and across the axis of the shaft at an angle of 45°, that forms the upper boundary of the popliteal space.

The front part of the trochlear faces for the patella are gone in our specimen.

_Measurements of Femur._

M. Greatest distal diameter across condyles ·178 Length of condyles ·079 Transverse diameter of shaft six inches above distal end ·121

_The Tibia_ (Plate VIII., Fig. 2).--The tibia is short, straight, and simple, slender in the middle, but much expanded at the extremities. The proximal end is especially massive, with deeply concave articular faces; the internal cotylus is the larger, and has its greatest diameter fore-and-aft, directly at right angles to the greatest diameter of the external.

The cotyli are separated by a smooth ridge, that is highest at its posterior termination. The tuberosity is high and massive, with a wide depression on its top for the reception of the ligament of the patella; the sides are deeply pitted by venous foramina. A section of the shaft at the lower part of the tuberosity would be subtriangular; while below it becomes more cylindrical, as it becomes smaller, reaching its shortest diameter about three fifths down the shaft. Below this it expands and forms the large subcircular distal end. The articular face is concave, with a slight, smooth ridge running fore-and-aft on its internal side. The malleolus is broad and low.

The _fibula_ is distinct, but very slender; its proximal end has a small circular face, which articulates with the tibia on a facet developed on the bottom of a projection of the tuberosity; the distal end is much flattened, but enters into the ankle-joint.

_Measurements of the Tibia._

M. Transverse diameter of proximal articulation ·158 Longitudinal diameter of proximal articulation ·123 Smallest circumference of shaft ·16 Greatest distal circumference above the articular face ·308 Diameter of distal articulation longitudinally ·082 Diameter of distal articulation transversely ·130 Width of tuberosity below pit for ligament of the patella ·075

Uintatherium princeps, _sp. nov._

Established on several portions of the head, vertebral column, and the limbs.

This species may readily be distinguished from the last by its larger size, the broad nasals with small tuberosities, the stronger zygomatic arches, and the sub-cylindrical centra of the dorsal vertebræ.

The _nasals_ are broad and flat for some distance behind the tuberosities. Although the animal was not adult, the nasal suture is almost obliterated, and is visible only on the inferior surface; in this respect it is very different from the _U. leidianum_, in which the suture persists throughout life; as is shown by the type specimen, which was past maturity. The tuberosities of _U. princeps_ are lower, broader, and more everted than in the preceding species; are not divided by a groove, but united together by a low rounded ridge, to which the surface of the nasals gradually rises from behind. The portion of the bones anterior is short, stout, and projects horizontally.

The _median_, or _maxillary_, _projections_ are apparently short and everted; they are somewhat compressed antero-posteriorly, and enlarge rapidly downwards. They are transversely oval in section.

The _posterior_, or _parietal_, _projections_ are different from any that we have yet seen. They are subtrihedral at base and flattened antero-posteriorly above. The upper margin is regularly arched, and is the thinnest portion of the process. The posterior face is perfectly flat, and the parietal crest makes a sharp angle with it, rising lower down than in _U. leidianum_; the frontal crest is also lower down than in that species, and the anterior face is strongly convex. The internal margin is rounded and straight, and does not show the longitudinal groove marked in the last species.

The _frontal_ has the eminences and depressions common to the members of the genus; but the superciliary ridge is unusually sharp and sinuous in outline.

The _squamosal_ is short, stout, and high; is but slightly curved outwards, but apparently projects somewhat downwards. The malar articulation is broad and flat, indicating the heaviness of that bone. As a whole the zygomatic arch is stronger, and probably shorter, than in _U. leidianum_.

The occipital condyles are proportionately rather small; they are placed on a long neck and project downwards. They are strongly convex from above downwards, but scarcely at all so from side to side. The internal border is slightly emarginate.

The _dorsal vertebræ_ are of about the same proportionate length as in _U. leidianum_, but are higher and wider; and the centra are subcircular in section, slightly contracted in the middle. The costal surfaces are wide and deep, and vertically oval in shape; they are placed partly on the centra and partly on the neurapophyses. The transverse processes are short, stout, and tuberous, and raised high above the centrum. There is a deep notch at the posterior edge of this process, at its junction with the neurapophysis. The neurapophyses are trihedral, somewhat low, and very stout, forming a wide neural canal.

The _ulna_ (Plate VII. Fig. 2) is thick, with a long and rugose olecranon. The shaft is long and stout; it shows a distinct medullary cavity. The distal end is small, and shows a low, heavy, styloid process.

A _metacarpal_ resembles the corresponding bone in _Dinoceras_, but is rounder and less rugose. There are two faces for carpal articulations, which meet at an open angle.

_Measurements._

M. Breadth over nasal tuberosities ·132 Length of nasal tip (anterior to tuberosities) ·033 Circumference of maxillary projection near the tip ·208 Vertical diameter of squamosal ·058 Transverse diameter of ditto at malar articulation ·045 Length of centrum of dorsal vertebræ ·070 Height of ditto ·083 Breadth of ditto below costal surfaces ·097 Breadth of pedicle ·058 Length of transverse process ·056 Extreme breadth of transverse process ·061

Found at Henry's Fork.

Uintatherium robustum. Leidy.

Cont. to Ext. Vert. Faun., p. 96.

A fragmentary skeleton from Henry's Fork.

RODENTIA.

PARAMYS, Leidy.

"Extinct Vertebrate Fauna of the Western Territories," vol. i. Hayden's Surveys, p. 109 _et seq_.

This genus of the gnawers is very closely allied to the squirrels and marmots. Dr. Leidy sums up the generic characteristics of the teeth thus:

"The four lower molars are proportionately narrower than in squirrels and marmots, the fore-and-aft exceeding the transverse. The crowns are short, square, tuberculate, and enamelled.

"The lower jaw is proportionately shorter and deeper than in most known rodents; the reduction in length being mainly due to a less development of that part of the bone in advance of the molars. To compensate for the difference in length, and to make room to accommodate the incisors, these teeth reach further back than usual.

"The acute edge of the hiatus between the molars and incisors is almost on a level with the alveoli, of the teeth, instead of forming a deep concave notch, so conspicuous a feature in the jaws of the gnawers generally."

_Species known._--

{ Paramys delicatus, Leidy. Loc. cit. { Paramys delicatior, Leidy. { Paramys delicatissimus, Leidy. Paramys robustus, Marsh.

Am. Journ. Sc. v. iv., p. 218.

Paramys superbus, _sp. nov._

Established on a single lower incisor.

The species indicated by this specimen is the largest of the genus as yet known. The tooth is subtrihedral in section, is stout, and shows but little curvature. The anterior and lateral faces are broad, and the under margin to which the sides converge, is narrow. The enamel is thick and is inflected so as to cover a small portion of the sides as well as the front.

_Measurements._

M. Transverse diameter of crown ·0062 Fore-and-aft diameter of crown ·007

Found at Cottonwood Creek.

AVES.

The expedition collected parts of four species of birds; a feather from Florissant Col. the distal ends of a humerus, and a femur and a portion of the shaft of an ulna (?) from the Bridger beds, but they are all too uncharacteristic for classification or description.

REPTILIA.

CROCODILIA.

CROCODILUS.

Crocodilus aptus, Leidy.

Contributions to Extinct vertebrate fauna of the Western Territories, p. 126.

Henry's Fork.

Crocodilus Grinnelli, Marsh.

American Journal of Science and Arts, vol. i., p. 465.

From Cottonwood Creek.

Crocodilus Elliotii, Leidy.

Cont. to Ex. Vert. Fauna, p. 126.

Represented by a perfect skull, and several vertebræ.

This fossil exhibits a form of skull which shows characters of both crocodile and alligator; the latter to a less marked degree. That it properly belongs to the former genus is shown by the notch in the upper jaw which receives the canine of the lower.