Sinclair: marsupialia of the santa cruz beds. 
335 
and, with the exception of Microbiotherium , a minute opossum, have been 
placed by Ameghino (1894, p. 108) in a suborder termed by him the 
Sparassodonta, a group which he regards as referable neither to the creo- 
donts, the placental carnivores, nor the carnivorous marsupials. A com- 
parison of the so-called Sparassodonta with existing carnivorous marsu- 
pials shows that they possess in common a large number of characters, 
either confined entirely to marsupials, or peculiar to but few additional 
orders. An examination of the following list will, it is believed, convince 
the reader that the Sparassodonta are true carnivorous marsupials and 
not worthy of subordinal rank. 
Marsupial Characters of the So-called Sparassodonta. 
1. A typical marsupial dental for- 
mula, 
4-3 JL 3^ 4 
3 f 3> 4’ 
2. The number of successional 
teeth is reduced below that char- 
acteristic of the placentals. 
3. The nasals are broad posteriorly, 
excluding from contact the fron- 
tals and maxillae. 
1. The presence of three incisors 
above and below is exceptional 
among marsupials. A fourth 
molar occurs in Otocyon and 
Centetes among placentals. 
2. According to Ameghino, the 
number of teeth having decidu- 
ous predecessors is greater in 
the Santa Cruz forms than 
among existing marsupials but 
less than in the placental Carni- 
vora. 
3. A posterior broadening of the 
nasals is characteristic of most 
existing marsupials. The con- 
tact between the maxillary and 
frontal is more or less extensive 
but may be reduced to zero as 
in some specimens of Tricho- 
surus vulpecula. Certain of 
the Creodonta ( Harpagolestes , 
Dromocyon , Mesonyx ) also show 
the posterior expansion of the 
nasals. 
