1831.] 
On the Dentition of Sciuropterus. 
257 
disposition it was very gentle, and a younger specimen, formerly in my posses- 
sion, became, in a little time, so tame, as to run freely about the house, without 
evincing any desire to escape. Faithful to the call, jumping on the lap, and 
licking, or playfully biting the hands of those with whom it was well acquainted* 
This affectionate little creature never seemed quite happy, but when being fondled 
and caressed. Unlike to some species of its kindred genera, it never injured the 
furniture, nor did any mischief whatever ; whilst its extreme beauty and grace of 
form, vying with its loveliness of disposition, well adapted it lor the reception of 
that affection we are all so ready to bestow upon the tribe, to which this interest- 
ing little animal belonged. 
Incisors. — The incisors of both jaws are of a dark brown colour, unfurrowed, and 
rather weak for an animal of so large a size : the lower pair have two flat surfaces 
at the apex, the external one being formed by attrition against the inner part of 
those of the upper. The latter are very short, and abruptly acuminated from 
the inside, to form a cutting edge : the surface so produced being somewhat 
concave. 
Molares. — The molares are sixteen in number, four in each side of each jaw, 
and in the upper the usual rudimentary, or accessory tooth, is placed in contact 
with the first molar. 
Lower jaw.— The molars are formed by two very regular, compressed folds of 
the enamel, projecting a little on the outer side, and two rather larger folds in- 
ternally, with irregular convolutions to form the superior surface. On the top of 
the first molar the anterior exterior fold rises into a prominence, and the other 
three have a similar projection formed by the anterior interior fold. In size the 
first molar is the smallest ; the second somewhat larger, and the third and fourth 
are larger still, and equal to one another. Inform; the first is rounded before 
and behind, the second and third are nearly square, being only a very little convex 
behind ; and the fourth is square on the anterior and exterior, and rounded on 
Hie opposite sides. Of fangs, the first molar has two, the anterior one being 
rather longer and more slender than the posterior ; the second and third have 
four fangs each, the two exterior being larger than the two interior ; hut the 
fourth molar has two rather small fangs in front, a large and long one behind, and 
an intermediate minute one on the inner side. 
Upper jaw.— The accessory tooth consists of a single prism, fixed in its socket 
so closely to the first molar, as to seem part of it: whether, as in the tribe gene- 
ra %, this tooth falls out when the animal attains to the adult state, I know not ; 
^ ut niy specimen was full grown. The first, second, and third molars are of 
nearly the same construction, the crown being formed by three folds of enamel 
^retching across, from the outer to the inner side of the tooth, where they are 
pinched up, as it were, into a crystalliform pyramidal tubercle ; of these folds the 
first and second are compressed, but the third is open. The fourth grinder is 
fofmed in a similar manner, on its upper surface, to the other three ; but it is 
smaller than they are, and rounded posteriorly and internally, instead of being 
Sc iuare on three sides, and rounded only internally. The fangs of the whole foiu 
c °nsist of two outer and one inner ; the former being straight, slightly divei gent, 
an <i small; but the latter is curved greatly, and divergent, and very laige, that 
second tooth having one or more small spines on its inner side, which aie 
received into a corresponding pit in the alveolar process. 
I* 1 the work which I have above quoted, it is stated, tliat in all the other 
squirrels, the lower incisors are long, directed forwards, and much moie nanow 
ai fo compressed than the upper, which are strongly curved. The molais aie four 
