92 MR. E. R. ALSTON ON THE GENUS ANOMALURUS. [Feb. 16, 
cervical 7, dorsal 16, lumbar 9, sacral 4, caudal 28 ; the latter are 
much elongated. The posterior ridge of the scapula is very salient ; 
and the humerus has a moderate deltoid ridge. The femur has a 
crest representing the third trochanter; and the slender fibula is 
quite distinct from the tibia; in Pteromys these bones are often 
closely united below, though not truly fused. 
Dentition.—The grinding-teeth of the Anomalure are four in 
number on each side above and below, the small anterior premolar 
of Pteromys being absent; this tooth, however, is lost early in life 
in many species of Squirrel. Their series converge in front ; and 
they are placed obliquely ; so that the crowns of the upper teeth 
look outwards, and those of the lower jaw inwards. These crowns 
are worn perfectly flat even in young individuals, exposing islands 
of cement separated by cross folds of enamel, which are .more 
directly transverse and less twisted than in the more complicated 
teeth of Pteromys. In the typical skull of A. beecrofti, in the 
British Museum, the cemental spaces are smaller and more isolated 
than in the other species. 
Viscera.—These, like the masticatory apparatus, differ much from 
those of the Sciuride, and, indeed, present peculiarities not met with 
in any other family of the order. 
Fig. 2. 
Czxeum of A. fraseri, natural size. 
The tongue resembles that of the Squirrels, but is narrower and 
more pointed. The circumvallate papille are two in number, and 
are placed transversely. 
The cesophagus has a short abdominal course after passing 
through the diaphragm, extending in 4. fraseri to about half an 
inch ; its epithelium is not continued beyond the cardiac orifice. 
