190 
ON THE LEMURIDiE. 
Genus Microcebus, Geoffrey St. Hilaire.— Gen. Char.~-}ieELd round; 
muzzle short and pointed; ears moderate, erect, rounded at the tips, and- 
nearly naked; eyes moderate, prominent, and bright. Fore limbs small; 
hand delicate; thumb short; fore-finger as short, or rather shorter, than the 
index finger; nails minute. Posterior limbs more developed than the ante¬ 
rior ; tarsal bones distinct; thumb long; first toe furnished with a claw; tail 
long, and slightly pencil-tufted at the tip. Incisors Canines molars 
on each side . The incisors above are small, the two central being the 
largest; these are separated from each other by an intervening space, as in 
'Lemur; the incisors below resemble those of Lemur; the canines above are 
small and pointed; behind each is a space, much more contracted in proportion 
than in Lemur., for the reception of the lower canines; these latter scarcely ex¬ 
ceed in size the first false molar, and present a similar shape and appearance; they 
incline considerably forwards, and when the jaws are close, fit in behind, and to the 
inside of the posterior edge of the upper canines. Of the molars above (on each 
side) the three first are false; they are simple and conical, with a minute notch 
anteriorly and posteriorly. The first two true molars have four acute points; 
those on the external edge of the crown being the largest; the last molar is the 
smallest, and has two outer points and one inner; of the molars below, the two 
first are false, simple, conical, and acute. 
The skulls of the Microcebi differ from those of the Lemurs, in being of a 
rounder form, and in having the muzzle much more abbreviated. In the skull 
of a Lemur before us, the total length of which is inches, the distance from 
the anterior margin of the orbit to the apex of the inter-maxillary bones is If 
inch, while in the skull of Microcebus murinus, the total length of which is If 
inch, the distance from the anterior edge of the orbit to the same point is two 
eighths and a half. Small as are the Microcebi, these animals are remarkable for 
their extreme activity, and the ease and rapidity of their leaping movements; 
it is, however, only at night that they indulge in sportiveness, being decidedly , 
nocturnal.' During the day they sleep rolled up like a ball, but rouse up from 
their torpor with the approach of grateful twilight. The brilliancy of their eyes, the 
tapetum lucidum gleaming through the round dilated pupil, indicates at once that 
night is their season of activity. Of their habits in a state of nature we know 
nothing, except that they are arboreal. In captivity they eat fruit and bread, but 
the character of their dentition indicates that insects, eggs, &c., form at least a 
great part of their diet. In their figure, (and especially in that of the Microcebus 
murinus) we are immediately reminded of the Lerot, or Garden Dormouse 
(Myoxus nitela), and this mutual resemblance is strengthened by a great simi¬ 
larity of manners. Like the Lerot, the Microcebi nestle in the holes of trees, 
which serve them as a dormitory, and a retreat in which to rear their young. 
