424 
ORIGIN OF LIFE IN AMERICA 
of palaeogeography. Professor Benham, moreover, has the 
advantage of residing in New Zealand, so that his views on 
these problems are of peculiar interest. To the south of New 
Zealand, between the latter and the antarctic regions, there 
are two groups of islands, viz., the Auckland and Macquarie 
islands. Now it is a specially noteworthy fact, remarks Pro¬ 
fessor Benham, that the species of earthworms from Mac¬ 
quarie island, and those occurring in the Auckland islands, are 
more nearly allied to South American and South African 
species than to those of the mainland of New Zealand. The 
evidence derived from the distribution of earthworms is, ac¬ 
cording to Professor Benham,* strongly in favour of the 
theory that New Zealand, South America and South Africa 
were once connected with one another by land. 
A study of the fresh-water crayfishes yields an even more 
remarkable testimony in support of the same view, at least 
of the theory that New Zealand and southern South America 
were connected by land. Dr. Ortmann points out that the 
family of crayfishes known as Parastacidae is confined to 
Australia, including Tasmania, New Zealand, southern South 
America and Madagascar. This family has thus an extremely 
discontinuous range and must be of great antiquity. Dr. 
Ortmann f believes that the Parastacidae existed in Australia 
in Upper Cretaceous times and thence spread by a land con¬ 
nection into Antarctica, from which Parastacus reached Chile. 
Subsequently Parastacus extended its range to Argentina and 
southern Brazil. Madagascar, he thinks, was not connected 
with the Antarctic Continent, and received its fresh-water 
crayfishes by another route. Besides this affinity in the fresh¬ 
water crayfishes of the Australian region and temperate South 
America, there are other crustaceans showing similar features. 
Mr. Geoffrey Smith ^ tells us that one of the commonest 
plankton organisms in the mountain lakes and tarns of 
Tasmania is the copepod crustacean Boeckella. Now this 
genus nowhere spreads into the tropics, yet reappears in 
New Zealand and southern South America. 
* Benham, W. B., “ Geographical Distribution of Earthworms,” 
pp. 329 — 335. 
t Ortmann, A. E., “ Distribution of Decapods,” p. 340. 
f Smith, Geoffrey, “ Naturalist in Tasmania,” p. 137. 
