_Microchærus_, Wood, Lond. Geol. Journ., i., p. 5 (1846).
_Heterohyus_, Gerv., Zool. et Pal. Fr., p. 202, pl. 35, fig. 14.
_Necrolemur_, Filhol, C. R., lxxxvii., p. 1112 (1873); id. Ann. Sc.
Geol., viii., p. 55, pl. iv., figs. 213-217 (1877).
This genus is distinguished from all other Lemurs by "the angle of the
mandible being produced into a large hook-like flange." (Flower and
Lydekker.) The orbits are large, indicating a nocturnal animal; the
inter-orbital space is wide, and distinguishes it from _Loris_. The dental
formula is I2/1, C1/1, P3/3, M3/3. The canine teeth are not prominent; the
anterior lower pre-molar is only slightly developed; a gap separates the
anterior and the median upper pre-molars.
This genus is represented by five species. MICROCHÆRUS ANTIQUUS (Filhol) is
of very small size, and has many affinities with _Galago_, as exhibited in
the well-preserved cranium that has been recovered from the Phosphorites of
Central France. The two lower molars have only one root. M. ERINACEUS,
{116}Wood, from the Upper Eocene of Hampshire; M. EDWARDSI (Filhol), from
Central France, a species larger than _M. antiquus_, presents dental
characters similar to the Galagos and the Mouse-Lemurs; M. PARVULUS
(Filhol), and M. ZITTELI (Schlosser), are both from the Quercy Phosphorites
of France; while M. ARMATUS is from the Eocene of Alsace, and M.
(CRYPTOPITHECUS) SIDEROLITHICUS from the Bonerg of Frohnstellen.