270 LLOYD'S NATURAL HISTORY. 
The type species of the genus, several others having been 
named, 
Distribution.— Tertiary formation of Patagonia. 
Before quitting these interesting, but still very imperfectly } 
known, extinct Patagonian Marsupials, a few words may be | 
added as to their importance from a distributional point of 
view assuming that (as appears to be justified by the number | 
of their incisor teeth) they are rightly regarded as allied to ; 
the Dasyuride. In the first place, it may be mentioned 
that it has long been a matter of common knowledge that 
there exist certain very remarkable relationships between the 
fauna and flora of all the great southern continents. For 
instance, among Mammals, the rodent family Octodontid@ is 
peculiar to South (including Central) America and Africa, in- 
cluding Algeria. ‘Then, again, among fishes, the family of the 
Chromide is confined to the rivers of South America and Africa, 
with one outlying genus in India; while the True Mud-fishes 
(Lepidosiren and Protopterus) are solely South American and 
Ethiopian, the third representative of the same family being 
the Baramunda (Ceratodus) of Queensland. Again, the 
connection between the flora of Africa and that of Western 
Australia is so intimate as to have induced Mr. Wallace to 
express his belief that there must have been some kind of 
land connection, although not necessarily a continuous one, 
between these two widely distant areas. ‘The connection 
between the fauna of India and that of Ethiopian Africa is 
now too well known to stand in need of comment. The 
matter does not, however, end here; for if we go back to 
the Secondary epoch there are equally striking evidences of 
the connection between the animals and plants of the southern 
continents. For instance, an extinct Saurian genus known as 
Mesosternum, which appears to have been allied to the Plesio- 
saurs of the Lias, is known from early Secondary strata in 
