. On the anatomy of vertebrates [electronic resource] . ain the longest. The inferior incisors areopposed to six minute incisors above, which are succeeded bya small canine and some small molars; but these are reducedin some, perhaps old, individuals, to a single tooth on eachside. The Phalangers, being provided with hinder hands and pre-hensile tails, are strictly arboreal animals, and have a closeexternal resemblance to the Opossums. They differ chiefly intheir dentition, and in accordance therewith their diet is moredecidedly of a vegetable kind. The interspace between thefunctionally devel
. On the anatomy of vertebrates [electronic resource] . ain the longest. The inferior incisors areopposed to six minute incisors above, which are succeeded bya small canine and some small molars; but these are reducedin some, perhaps old, individuals, to a single tooth on eachside. The Phalangers, being provided with hinder hands and pre-hensile tails, are strictly arboreal animals, and have a closeexternal resemblance to the Opossums. They differ chiefly intheir dentition, and in accordance therewith their diet is moredecidedly of a vegetable kind. The interspace between thefunctionally developed incisors and molars in both jaws alwayscontains teeth of small size and little functional importance, andvariable not only in their proportions but their number. Theconstant teeth are the ^—4 true molars, and the ^--3- incisors. m • 4—4 > 1—1 The canines, c, fig. 228, are constant in regard to their presence,but variable in size ; they are always very small in the lower jaw :the functional premolars, p 3, are always in contact with the. Dentition of Phalaugista vulpiua. Dentition of Cooks Phalanger. molars and their crowns reach to the same grinding level; some-times the second premolar is similarly developed in the upperjaw, as in the Phal. Cookii, p 2, fig. 229, but it is commonlyabsent; the first premolar, p l, is a very minute tooth, shapedVOL. III. u 2S0 ANATOMY OF VERTEBRATES. like a canine : thus, in the upper jaw, between the posterior orfunctional premolar, p 3, and the incisors, z, we may find threeteeth, as in Phal. Cookii, or two teeth as in Plial. vulpina, thefirst being the canine, c. In the lower jaw similar varieties occurin these small and unimportant teeth: e. g. there may be betweenthe procumbent incisors and the posterior premolar, either threeteeth, as in Phal. Cookii; or two, as in Phal. ursina; or one, as inPhal. vulpina. The most important modification is presented bythe little Phal. gliriformis and Petaurus (Acrobates) pygm&us,fig. 219,
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