72 ZOOLOGICAL GARDENS. 
universality of certain characters, the instance before 
us furnishes a striking example. Relying solely on the 
discrepancy or agreement of the dentary systems, and 
putting entirely out of the question all consideration of 
other and essential points of structure, M. Frederic 
Cuvier has reunited the old genus Phalangista, in order 
again to subdivide it into two incongruous and hete- 
rogeneous groups; in the one confounding two well 
marked species of flying Petauri, not only with the 
climbing Phalangistse of New Holland, but with the 
naked-tailed and strictly prehensile Couscous of the 
Moluccas ; and repaying the other group, which he 
had so unnecessarily dismembered, by the addition of 
a true Phalangista, whose only pretensions to such an 
association are made to depend on a somewhat similar 
arrangement of the teeth. By thus confining himself to 
a single character, he has broken up the regular series 
of affinities which connected together three marked, but 
still closely allied, gradations of form, to substitute an 
arrangement which has no other recommendation than 
its accordance with the theoretic views of its author. 
In such a case we cannot hesitate in giving to the 
organs of locomotion, combined with the general habit, 
that precedence before those of mastication, which 
under other circumstances we are generally in the habit 
of conceding to the latter ; and we feel the less repug- 
nance to adopting this course, because it is admitted 
that the dentary formula is in these animals subject to 
some variation, and because zoologists are by no means 
agreed with respect to its exact definition. 
The teeth of the Squirrel Petaurus agree generally, 
according to M. Frederic Cuvier, with those of the 
Phalangistas. They are consequently thirty-eight in 
number, twenty occupying the upper jaw, and eighteen 
