MARSUPIALIA. 
Genus DASYURUS. (Fig. 81.) 
Dasyurus Ursinus, one-third natural size. 
4 4—4 . 1—1 
Incisors 5—Z; canines 7 ; premolars 
2—2 4—4 
ino? molars any = 42. 
The eight incisors of the upper jaw are of 
the same length and simple structure, and are 
arranged in a regular semicircle without any 
median interval. The six incisors of the lower 
jaw are similarly arranged, but have thicker 
‘crowns than the upper ones. The canines 
__ present the same or even a greater relative de- 
velopment than in the Thylacine: in an extinct 
species of Dasyurus* they had the same form 
and relative proportions as in the Leopard. 
The spurious molars have a pointed com- 
ressed triangular crown with a rudimental tu- 
_bercle at the anterior and posterior part of its 
base. The grinding surface of the true molars 
_in the upper jaw is triangular; the first presents 
four sharp cusps, the second and third each 
‘five, the fourth, which is the smallest, only 
_ three. In the lower jaw the last molar is 
nearly of equal size with the penultimate one, 
__and is bristled with four cusps, the external one 
being the longest : the second and third molars 
have five cusps, three on the inner and two on 
the outer side; the first molar has four cusps: 
these are all sharply pointed in the young 
animal, in which the posterior tubercle of the 
posterior molar in the lower jaw is divided 
_ into two small cusps. 
The carnivorous character of the above den- 
tition is most strongly marked in the Ursine 
_ Dasyure or Devil of the Tasmanian Colonists, 
_ the largest existing species of the genus, and 
_ a most pestilent animal in the poultry-yard or 
: er. 
‘Genus PHASCOGALE. ( Fig. 82.) 
Phascogale penicillata. 
* Dasyurus laniarius, Owen: the fossil remains 
of this species were discovered with those of two 
tic species of Kangaroo in the bone-caves of 
ellington Valley, Australia, by Major, now Sir 
Thomas, Mitchell. 
wees, ee 
259 
4—4 1—1 
Incisors 323; canines =: premolars 
3—3 — 
3—3 5 4—4 ° 
In the present dental formula may be dis- 
cerned a step in the transition from the Da- 
syures to the Opossums, not only in the in- 
creased number of spurious molars, but also 
in the shape and proportions of the incisors. In 
the upper jaw the two middle incisors are 
longer than the rest, and separated from them 
by a brief interval ; they are more curved and 
project more forward. The three lateral in- 
cisors diminish in size to the outermost. The 
middle incisors of the lower jaw also exceed 
the lateral ones in size, and project beyond 
them but not in the same degree, nor are they 
separated from them by an interval, as in the 
upper jaw. The canines are relatively smaller 
than in the Dasyures. The spurious molars 
present a similar form, but the third in the 
lower jaw is smaller and simpler than the two 
preceding ones. The true molars resemble 
those of the Dasyures. 
The general character of the dentition of 
these small predatory Marsupials approximates 
to the insectivorous type, as exemplified in 
the Shrew, Hedgehog, &c. among the placental. 
Mammalia, and corresponds with the food and 
habits of the species which thus lead from the 
Sarcophagous to the Entomophagous tribes. 
The interval is further diminished by a 
lost marsupial genus which forms one of the 
ancient Mammalia that have rendered the 
oolitic formations at Stonesfield so celebrated. 
This genus, which I have called Phascolothe- 
rium, presents the same numerical dental formula 
as in Phascogale, viz. 
— 46. 
molars 
. 1? . 2. 
Incisors 33 or 44; Canines qj ° 
1? —? 
premolars §3? molars 7—7- 
But the incisors and canines are separated by 
vacant interspaces, and occupy a large pro- 
portional space in the dental series: the true 
molars resemble those of Thylacine. ; 
Tribe II. ENTOMOPHAGA. 
This is the most extensive and varied of the 
primary groups of the Marsupial order. In 
the system of Cuvier, the species of this tribe 
are united with those of the preceding to form 
a single group characterized by the presence of 
long canines and small incisors in both jaws: 
but in most of the Entomophagous genera of 
the present classification, the canines present a 
marked inferiority of development, and the 
species are consequently unable to cope with 
animals of their own size and grade of organ- 
ization, but prey, for the most part, upon the 
smaller and weaker classes of invertebrate 
animals. Their intestinal canal is complicated 
by a moderately long and large cecum; and 
while, in the Sarcophaga, the feet are con- 
structed upon the plan of those of the ordinary 
placental Digitigrades, they offer in the pre- 
sent tribe a variety of well-marked modi- 
s.2 
