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456 DENTAL ANAT03fY.

situated just internal to the posterior part of the great superior sec-
torial, so as to be completely hidden in an external view of the ja\v.
In an extinct species [Hi/irna exhnia) there were four premolars in the
' " " ~ ' "
lower juw, giving the formula 1. 1, C. y, Pm. ^, M. ^ = 3G. The infe-
rior sectorial also has a well-defined heel.
Fig. 235.
In the more ancient or Miocene represent-
ative of this family {Hycenidh (jrccca,
Fig. 235) the superior molar is nmch
larger and has a more posterior position
;
the inferior sectorial (Fig. 236) has a rela-
tively large basin-shaped heel., and there is
a small second true molar behind it. It is
through this genus that the transition is
effected from the Hyai\i(]w to the (MnUke
Superior Sectorial and First Molar of bv W'ay of IditherivDl and AUuVodon.
Hyanictisgra.caX^iterV.^nAry). ^
^j^^ ^^^^^^^^ fomuda of the Vk€rkJ(B
varies somewhat by reason of decrease in number of the premolars
and molars. The more important of these will be noticed after we have
first described the dentition of a typical example of the family, which is
found in the genus Herpedes, or the mongoose. The dental formula is
I. 1 c. x.] Pni. 4^ M. = 40. The in-
I
Fig. 236. cisors of the upper series have flattened
oval crowns without lateral lobes, in-
creasing in size from first to third ; the
canines are long, pointed, and recurved
;
the first three premolars have the usual
pattern, but are devoid of accessory
cusps. In the fourth premolar or su-
perior sectorial the blade is composed
of the usual two posterior cusps, sepa-
rated l)y a fissui'e remarkable for its
Frastnient of Lower Jaw of //. ijra'ca, show-
ing sectorial and second molar (after depth. There is also a rudimental an-
Gaudry).
terior basal lobe, which arises from the
cingulum. The internal lobe is unusually strong, and sends a trenchant
ridge backward and outward to join the principal cone. The next
tooth, or first true molar, is tritubercular, with two external and one
internal cusp ; the crown is remarkable for its transverse extent. The
last molar is relatively small, and has a more internal position, possess-
ing a bicuspid crown. The decrease in size of the true molars from that
of the great sectorial, and the strongly inward curvature of the tooth-line
behind, are more i)ronounced than in the dog, and altogether interme-
diate between that of the latter animal and the cats.
The incisors of the lower jaw are smaller than the corresponding
teeth above, and the sununits of their crowns are distinctly notched ;
the canines are like those of the nj)per jaw, while the premolars have
basal cusps which are largest behind. The first true molar or inferior
sectorial furnishes a pattern intermediate between the tuberculo-sectorial
and the well-defined sectorial. The ])rimitive cone and anterior basal
l()b(\s are connected into a blade, the internal tubercle being large and
furnishing the characteristic triangular appearance of this portion of the