Fauna and Flora of New Zealand. 429 
greater extension of southern lands during a warm Miocene 
period. Now Dr. P. Martin Duncan is certainly of opinion that 
the sea in this portion of the southern hemisphere was much 
warmer in the Miocene period than at present, and he has 
suggested that this was due to an extension of the Antarctic 
Continent up to 50°8.*; but, on the other hand, Mr. Darwin 
considered the Eocene sea of Chili to have been no warmer 
than at present, and Mr. Tenison-Woods says that “the whole 
evidence of the [Tertiary] fossil corals shows a climate and 
isolation in the New-Zealand fauna not very different from 
the conditions which exist now,” and that the Tertiary fauna 
of New Zealand generally “is not that of a warm sea, nor like 
what we should find on the warmer extra-tropical portions of 
the Australian coast” +. The Miocene Mollusca appear to 
me to indicate a rather warmer sea; but, as several of the 
species still live as far south as Foveaux Straits t, no eleva- 
tion of temperature sufficient to take tropical and subtropical 
plants and animals to 50° 8. is probable; and, in addition to 
other difficulties presently to be mentioned, I shall, I think, 
be able to show that the South-American connexion is of a 
far older date than the Miocene. Before doing so, however, 
it will be necessary to give a short review of the fauna of the 
Australian region. 
In Mr. Wallace’s opinion the deep oceans, 7. e. the Pacific, 
Atlantic, and Indian Oceans, have been in existence from the 
earliest geological times. All the principal groups of land 
animals, he thinks, have originated in the northern hemi- 
sphere, and have gradually migrated southwards through the 
continental extensions’ of America, Africa, and Australia 
(including the Indian archipelago), comparatively few having 
subsequently spread east and west by means of antarctic islands 
now submerged. If this be true, it is evident that the fauna 
of Australia ought to be more nearly allied to that of South 
Africa than to that of South America, because the connexion 
with the former by way of India is so much closer than the 
connexion with the latter by Kamschatka and Alaska. Let us 
see if this is so. 
The Australian Mammalia are very peculiar, and are more 
closely allied to the Jurassic mammals of Kurope and America 
than to any now living. The marsupials of America are 
related to the Hocene marsupials of Kurope, and are evidently 
* Quart. Journ. Geol. Soc. 1876, p. 345. 
+ ‘ Paleontology of New Zealand,’ part iv. p. 4 (1880). 
} Such as Voluta pacifica, Triton Spenglert, Parmophorus unguis, Chione 
Stutchburyi, Tapes intermedia, Pectunculus laticostatus, Waldheimia lenti- 
cularts, and others. 
