corresponding length in the quagga, while the parts are in other respects as large as those of the domestic horse. The maxillary bone is produced posteriorly to the last molar as far as in E. caballus. In E. occidentalis this distance is less. The last superior molar is larger than the penultimate in E. intermedius; it is equal or larger in E. caballus, while it is. smaller in E. occidentalis.* In the E. occidentalis figured by Leidy (Exct Mamm. Dak. Nebr. Pl. xxi), and in the one figured by me (Ann. Rept. Geol. Surv. Tex. 1892), the palatine foramen is opposite the penultimate molar. In the E. intermedius as in the E. caballus it is opposite the last molar. In the symphysis the mental foramen is entirely anterior to its posterior border, as in E. occidentalis. This specimen belonged to a mare, as it has no trace of canine tooth, the first time that I have observed this character in an extinct North American horse.

The Equus intermedius is then intermediate between the E. occidentalis and the E. caballus. It agrees with the latter in its molars and palatine foramen; with the former in the occipital region, wide incisors and short muzzle, and tends towards E. fraternus in the incisor cups. From E. major it differs in the much less complex enamel folds.

M.M.

.143

86

30

31

25

30

36

29

40

"mandible from p. m. iii to external border of

EQUUS FRATERNUS Leidy, Proceeds. Phila. Acad., 1858, p. 11; Postpliocene Fossils of S. Carolina, Tuomey and Holmes, 1859, p. 100, Pl. xv Figs. 6, 8, 16, 17, 18; Pl. xvi, Figs. 23, 27-29.

This species is represented by a considerable number of teeth together

See Ann. Report Geolog. Survey of Texas, 1892, Plate xxii, Fig. 3.

with part of a lower jaw with symphysis, in the museum of the Wagner Free Institute of Science, of Philadelphia.

66

Leidy remarks of this species that it is not possible to distinguish it from the E. caballus by the teeth, and he has not offered any other characters 'by which to distinguish it. I was therefore compelled to omit mention of it from my table of the American species of Equus, published in the Proceeds. American Philos. Society, 1884, p. 10, and Annual Report of the Geological Survey of Texas for 1892, Vertebrate Paleontology," p. 66. Subsequently I had the opportunity of examining the dentition and mandible of a horse from Florida, determined by Leidy as the E. fraternus and preserved in the museum of the Wagner Free Institute of Science of Philadelphia. One set of dentition belonged to a young horse and the other to an adult. In both the posterior wall of the cup of the incisor teeth is extensively interrupted, so as to reduce the triturating surface to a single crescent. On account of this character I proposed to refer the species to a distinct genus, which I called Tomolabis, regarding it as a degenerate offshoot of the genus Equus. A reëxamination of the specimens together with the observations above recorded on the incisors of the E. intermedius, suggests that an examination of a larger amount of material will be desirable before the validity of this genus can be established, since it is possible that a full series of gradations between the characters of the incisors in E. fraternus and E. intermedius may be established.

It is demonstrated by the specimens in the Wagner Free Institute that there existed in Florida during probably Plistocene time, a species of horse of considerably smaller size than either the E. major, E. intermedius or E. occidentalis, and characterized by an enamel plication of the molars similar to that of the E. intermedius, that is, generally a little more complex than is characteristic of the E. caballus. What characterizes it especially is the small size of the protocone, which has an anteroposterior diameter considerably less than in the species named, not differing much, however, from some specimens of the common horse. Thus this measurement enters the anteroposterior diameter of the grinding surface 2.5 times, rarely twice and one-third times, and in one instance only, twice. In the true molars of E. intermedius, E. occidentalis and E. major the proportion of the two diameters is 1 to 1.5 in the great majority of teeth. This peculiarity with that of the incisors indicates, I think, that this horse must be regarded as a distinct species or race.

The part of the mandible referred to contains all the incisors, and the second and third molars of the left side. The latter teeth agree with the largest separate teeth of the collection in characters. The length of the jaw anterior to the p. m. iii is equal to that of the corresponding part of the E. intermedius and is considerably shorter than in the E. caballus. It must be borne in mind that the molars are smaller than in the ordinary Equus caballus, so that this dimension is relatively longer than in the E. intermedius. Appropriately the symphysis is not so wide at the external incisors as in the latter, and is less contracted at the posterior part of

1895.]

[Cope.

the symphysis, thus again resembling the E. caballus. The mental foramen is behind the symphysis as in E. caballus, but the crowns of the incisors have a transverse width proportionately equal to that of the incisors of E. intermedius. This jaw belongs probably to a mare, as there is no canine.

Both superior and inferior molars have the dentine marked with delicate longitudinal ridges. This can of course only be seen where the cementum has been lost.

In the inferior molars the relations of the metaconid to the metastylid are as follows. In two inferior molars (separate) they meet at a sharp angle; in five teeth they meet at a sharp angle, but gape widely apart; in three teeth the groove between them is rather shallow, as in the E. occidentalis, but not so wide as in the E. eurystylus and E. minimus.

Length from inferior p. m. ii to edge of inferior incisors.....123
Width symphysis at base of I iii...............

... 58

In this form we have then one which, as remarked by Leidy, approaches nearer to the E. caballus than any other. That it is a distinct species from the common horse I strongly suspect, from its peculiar incisors, and thinner enamel plates of the molars; but it will be very desirable to examine other parts of the skeleton and especially of the skull in order to establish its true status.

It remains to be understood to what species Leidy gave the name of Equus fraternus. In the paragraph where Leidy first named it no locality from which typical specimens were obtained is mentioned, and the description will apply equally well to the E. intermedius. In Tuomey and Holmes' Fossils of S. Carolina, Leidy first definitely locates the species as based on specimens found near Charleston, S. C. He figures a number of molar teeth, some of which probably belong to the E. intermedius. The superior molar, which is first described, is figured on Pl. xv, Fig. 6 of that work. Unfortunately, the protocone of that tooth is largely broken off, but enough remains to show that it had the very small anteroposterior diameter characteristic of the Floridan teeth, and in other respects it agrees with them, except that it is larger than usual. This is, . however, not sufficiently marked to be important. I therefore regard it as the type of the species as described by Leidy.

DESCRIPTION OF PLATES.

All the specimens figured are the property of the Tulane University.

PLATE X.

Fig. 1. Superior molars of Mylodon harlanii Ow., from separate teeth; nat. size, from below.

Fig. 2. Mylodon harlanii Ow., grinding face of inferior m. iii from above.

Fig. 3. Mylodon renidens Cope, maxillary bone with teeth, from below. Fig. 4. Mylodon sulcidens Cope; Inferior molar iii profile; a from above.

PLATE XI.

Fig. 5. Mylodon renidens Cope; a, b, c, Inferior molars ii, iii and iv from above.

Fig. 6. Mylodon renidens Cope; third inferior molar.

Fig. 7. Mylodon sulcidens Cope; a, superior m. iv from below; b, superior m. iv from inner side.

Fig. 8. Equus intermedius Cope, last five superior molars from below; nat. size; with posterior extremity of maxillary bone.

PLATE XII.

Fig. 9. Equus intermedius Cope; Symphysis mandibuli from above; nat. size.

Fig. 10. Equus intermedius Cope, basioccipital and part of the basisphenoid and adjacent regions; nat. size.

An Early Essay on Proportional Representation.

By Edmund J. James

(Read before the American Philosophical Society, December 6, 1895.)

On May 3, 1844, the American Philosophical Society, of Philadelphia, gave Thomas Gilpin, Esq., permission to read a printed paper, entitled, "On the Representation of Minorities of Electors to Act with the Majority in Elected Assemblies." The paper had been printed by the author at his own expense and dedicated to the Society. The date at the end of the paper is May 1, 1844; in the dedication May 3, 1844.

Two copies of the pamphlet are in the Philadelphia Library; one is reported to be in the Boston Athenæum Library; one is in the Harvard College Library; one in the Franklin Institute Library; one in the library of James Monaghan, of West Chester, and there are probably also copies in other libraries. It is a small pamphlet of fifteen pages and was reprinted in the Penn Monthly in 1872.

This paper is remarkable as being one of the first systematic discussions