GENUS ANAPTOMORPHUS.
Anaptomorphus, Cope, Proc. Amer. Phil. Soc., 1872, p. 554; id., Rep. U. S. Geol. Surv., iii., p. 245, pl. xxiv. e, fig. 1; xxv., fig. 10.
This genus was founded by Cope on an almost entire cranium discovered in the Bridger (Eocene) beds of the upper Valley of Green river, and on other remains from what is known as the Wasatch formation of the Big-Horn Basin in Wyoming Territory, in North America. The external upper incisor is small and set close to the small canine; the pre-molars have each a large external and a smaller internal cusp; the true molars are wide and have one internal and two external cusps. In the lower jaw the two anterior molars are four-cusped, with a transverse ridge between the anterior pair, and an oblique ridge between the hind inner, and the front outer, cusp; the posterior is three-cusped and has a heel. The orbits are enclosed, as in typical Lemurs. Not less typical characters are the position of the lachrymal foramen, external to the orbit, and the unossified halves of the lower jaw. "Its dental formula (I22, C11, P22, M33) agrees only with the Indrisinæ. But no known Lemuridæ possess anterior lobes and cusps on all the pre-molars, so that in this respect, as in the number of its teeth, this genus resembles the higher Monkeys, the Simiidæ and Hominidæ, more than any existing member of the family.... It has ... a number of resemblances to Tarsius, which is, perhaps, its nearest ally among the Lemurs, although that genus has three pre-molars.... There is no doubt but that the genus Anaptomorphus is the most Simian Lemur yet discovered...." (Cope.)
The species included in this genus are A. æmulus (Cope), which did not exceed the size of a Marmoset or a Red Squirrel, and had short erect incisors; A. homunculus (Cope), a species founded on a cranium without a lower jaw, with the orbits not so large as in Tarsius, and the skull wide behind the eyes. "The A. homunculus was nocturnal in its habits," according to Professor Cope, "and its food was like that of the smaller Lemurs of Madagascar and the Malayan islands. Its size is a little less than that of the Tarsius tarsius."
Two other insufficiently characterised genera, both considered to be primitive Lemuroids, are Plesiadapis, Gervais, containing the species P. remensis, P. gervaisi, P. tournesarti, and P. daubrei, from the Lower Eocene strata of Rheims, which have five-cusped lower molars, and enlarged upper and lower incisors; and Protoadapis, Lemoine, with one or two high front cusps, and a low heel to its three pre-molars; the anterior molars with two pairs of opposite cusps, the posterior molar with a fifth cusp on the hind border. P. crassicuspidens, Lemoine, and P. recticuspidens, Lemoine, are its two species.
FAMILY ADAPIDÆ.
The different species associated together under this family are abundantly known from the Upper Eocene of France, England, and North America. They are remarkable in having an extra pre-molar in both jaws, the dental formula being I22, C11, P44, M33.
GENUS ADAPIS.
Adapis, Cuvier, Ossem. Foss. (2) iii., p. 265 (1822); Flower, Ann. and Mag. N. H., xvii., (1876), p. 323.
Palæolemur, Delfort., Act. de la Soc. Linn. Bord., xxix., pp. 87-95, pl. 5 (1873); id. C. R., lxxvii., p. 64 (1873).