_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 (I2/2, {118}C1/1, P2/2, M3/3) 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.
{119}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 I2/2, C1/1, P4/4, M3/3.