976 THE AMERICAN NATURALIST. — [VOL. XXXIII. 
structs this bridge across the South Pacific from Chile to Samoa and 
thence to New Zealand, that of Forbes, which assumes an immense 
Antarctic continent, and that of Pilsbury and v. Ihering, which 
accounts for the similar forms in South America, Tasmania, and 
Australia by the hypothesis of a former more extensive Austral con- 
tinent which subsequently became united with South America at 
Cape Horn, Hedley gives his own solution of the problem. He 
says that “during the Mesozoic or older Tertiary, a strip of land 
with a mild climate extended across the South Pole from Tasmania 
to Terra del Fuego, and that Tertiary New Zealand then reached 
sufficiently near to this Antarctic land, without joining it, to receive 
by flight or drift many plants and animals.” This “ Antarctica” was 
of an unstable character, “at one time dissolving into an archipel- 
ago, at another resolving itself into a continent.” ‘Thus a deep gulf 
extended from Tasmania to Cape Horn, stretching within a few 
degrees of the pole, and this assumption would tend to explain 
some facts of distribution of marine shallow-water animals. 
It seems to us that this theory has some advantage over the other 
theories mentioned, yet it is perhaps premature to form a distinct 
idea as to the connection of the southern ends of the present conti- 
nents. That such was present before or at the beginning of Tertiary 
times seems to be beyond doubt, but for the actual construction of 
this bridge the data at hand seem to be too imperfect. But this 
much we may safely assume, as Hedley does, that this bridge was 
no constant and solid mass all the time it existed, but was repeat- 
edly broken up into parts, making possible an exchange of life in 
different directions. 
The particular idea of Hedley on this subject, even if we do not 
at once accept it, is at least worth considering seriously, and the fre- 
quent and very complete references to previous writers form one of 
the features of his article that make it the more valuable for the 
student of this fascinating question of the “ Antarctica.” se tö 
ZOÖLOGY. 
Accessory Bladders of Turtles. — F. W. Pickel’ has studied the 
accessory bladders of turtles, and finds these organs present in semi- 
1 Pickel, F. W. The Accessory Bladders of the Testudinata, Zodlogical Bul- 
-letin, vol. ii, No. 6, pp. 291-301. September, 1899. 
