MICROCHZRUS. IT5 
Wasatch strata of Wyoming, and the Puerco beds in New 
Mexico. Their dental formula is the same as that of existing 

Lemurs, namely 1,4, C5, P33, M3. In some of the 
genera there is a tendency to develop, as Cope has pointed 
out, large cutting teeth in the position of incisors, “ thus 
approaching the Aye-Aye.” The posterior pre-molars are 
more simple than the anterior true molar, a character which 
indicates some relationship to the Mouse-Lemurs (Cziroga/e). 
The mastoidal or posterior portion of the ear-capsules, and 
the neighbouring squamosal region of the cranium are swollen, 
as among the Galagos. 
GENUS MICROCH#ERUS. 
Microcherus, Wood, Lond. Geol. Journ., i., p. 5 (1846). 
FTeterohyus, Gerv., Zool. et Pal. Fr., p. 202, pl. 35, fig. 14. 
wvecrolemur, Vilhol, C» R.,. Ixxxvit., p: 1112: (1873):; -1d.. Ann. 
Sc. Geol., vill, 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, indi- 
cating a nocturnal animal; the inter-orbital space is wide, and 
distinguishes it from Zorvis. The dental formula is I?, C}, 
P3, M3. 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. MicrocH&RUS 
ANTIQUUS (Filhol) is of very small size, and has many affinities 
with Ga/ago, 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, 
ie. 
