320 
PACIFIC SCIENCE, Vol. XIX, October 1965 
have been collected in New Zealand is 10° C 
As far as Dr. Russell knows this is the first 
time members of the genus Brachionus have 
been collected in polar waters. 
The presence of Brachionus and other cos- 
mopolitan genera in Antarctic assemblages 
raises the question of how they were intro- 
duced into the south polar region. Several 
means of distribution have been suggested: 
1. Continental association. According to Ku- 
enen (1950) there are several theories to ac- 
count for the dispersal of plants and animals 
to (and from) Antarctica. Of these the conti- 
nental drift hypothesis of Wegener (1924) 
appears to be the most popular. It postulates 
the Paleozoic existence of Gondwandaland from 
which, in the early Mesozoic, the continents of 
the southern hemisphere broke off and drifted 
apart. Stille (1944) and others deduce from 
seismic evidence that much of the area between 
Antarctica and Australia is a slumped continent. 
Hedley (1911) and his school believe in an 
ancient isthmian link between Australia, Ant- 
arctica, and South America. Hedley’s thesis is 
invoked by Du Rietz (1940) and others to ex- 
plain the bipolar distribution of common plants. 
2. Dispersal by the wind. Allee et al. ( 1950) 
mention "plankton of the air” consisting of 
dessicated animals and plants, cysts, eggs, etc., 
which drift with the air currents, sometimes as 
high as the stratosphere. Upon falling to earth, 
they resume normal activity where the environ- 
ment is favorable. 
3. Distribution by birds. According to Hesse 
et al. (1958) water birds are transportation 
media for aquatic microorganisms. Not only 
may biota be carried externally but cysts and 
eggs may be eaten and excreted. Eklund ( 1961 ) 
says skuas were often seen to drink at fresh- 
water ponds. According to Stead (1932), Cata- 
racta antarctica (C. skua lonnbergi) range from 
New Zealand to Antarctica. 
Considering the application of the foregoing 
agencies to Clark Peninsula pools, that of con- 
tinental association can be discarded for two 
reasons. First, there is no fossil evidence that 
non-marine fish, amphibians, reptiles, or mam- 
mals were ever present in Antarctica. Second, 
and most cogent, the pools were submerged, 
in Recent time, in the sea. While distribution 
by the wind may play a role in dispersion of 
fresh-water biota, the dominant one is likely 
that of birds. Skua gulls are capable of trans- 
porting organisms from a pool in New Zealand 
to one in the Antarctic. 
ACKNOWLEDGMENTS 
The author gratefully acknowledges the as- 
sistance of Dr. C. R. Russell of Canterbury 
University; Dr. I. M. Lamb and Dr. E. E. Diech- 
mann of Harvard College; and J. T. Hollin of 
the Institute of Polar Studies, Ohio State Uni- 
versity. 
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