850 
PBTAURISTA. 
the P. tagnanoides the type of his first section, to which he 
gives the name Petaurista , and Pet . pygmceus the type of 
his second section. From the first of Desmarest’s subdivisions 
we shall have to separate certain species which differ from 
his type, and, in fact, it will be necessary to restrict liis 
sectional name to the P. taguanoides . The dental formula in 
this animal is, incisors, * ; canines, ^ ; premolars, ~ ; true 
molars, The incisors of the upper jaw are arranged 
laterally, and the three on either side are placed close together; 
the two foremost, belonging to opposites sides of the jaw, are 
separated from each other by a narrow space ; they are 
narrow 7 at the base, and wide and somewhat compressed, 
above the base. The next incisor, on either side, is larger 
than the posterior one, and about half the height of the 
first ; narrow at the base, and wide and truncated at the 
apex. The third incisor is small, and but little expanded at 
the apex. The canine is small, being in size about equal to 
the posterior incisor ; its tip is rounded, and it springs from 
the maxilla a little behind the intermaxillary suture. The first 
false molar is minute and conical, separated by a considerable 
space from the canine, and also from the second premolar, and 
has but one fang. The next tw 7 o premolars have two fangs 
each ; they are broad at the base, and compressed at the 
apex : the foremost presents an anterior larger, and a posterior 
small and compressed tubercle; the hindermost is divided at 
the tip into three compressed cusps. The true molars arenearlv 
square, but rather longer than broad ; the crown of each, 
with the exception of the last, presents four angular cusps. 
In the last there are but three of these cusps; two in front 
and one behind. The incisors of the lower jaw are large, 
nearly cylindrical at the base, and somewhat dilated, flattened 
and pointed beyond, and have two sharp edges. The space 
between the incisors and principal premolar, I have found 
edentate in two skulls of P. taguanoides , but in a third 
