TRANSACTIONS OF SECTION D. 509 
In the United States the Great Lakes have been explored by Jennings, 
and the Illinois River by Prof. Kofoid, and some few other regions by Kelli- 
cot, Hempel, and others, and, though about 300 species have been recorded, 
no very peculiar and distinctive American forms have been revealed. 
In Canada, unfortunately, no one has yet been found to take up their 
study, and the Rotatorian fauna of the Dominion therefore remains quite 
unknown. 
From South America 80 species have been recorded by Prof. Von Daday 
in plankton collections made in Paraguay, of which three only are described 
as new, all the others being already known in Europe. 
During the British Association meeting in South Africa in 1905, I 
myself collected in various widely separated localities—Capetown, Orange 
River Colony, Transvaal, and Rhodesia—in all 63 species, all of which, 
except one, were already known in other parts of the world. Even in the 
Zambesi River, where I obtained 38 species in pools just above the Victoria 
Falls, all of them without exception were already known outside Africa. 
Gunson Thorpe, W. Milne, Thos. Kirkman, and James Murray have re- 
corded about 100 more species from other parts of South Africa, of which 
less than half a dozen were new forms. 
From Central Africa I have examined collections made by Dr. W. A. 
Cunnington in Lake Tanganyika and adjacent rivers, and, though this 
material was very poor in Rotifera, I obtained about 40 species, all known 
already in Europe. 
In moss collected in the Sikkim Himalaya in India, Mr. Jas. Murray 
observed 36 species, mostly Bdelloids, of which five only were as yet unknown 
in Europe. 
As regards distribution in Arctic and Antarctic regions, I may mention 
that Dr. Bergendal has recorded 82 species, belonging to 38 genera, from 
Greenland, where the pools and shallow lakes are frozen, often to the bottom, 
for eight months in the year. With the exception of a few new species found 
there for the first time, all these forms belong to the ordinary European 
fauna. 
In collections from two lakes in Iceland, Dr. Wesenberg-Lund found 
nine species of Rotifers, all having a wide distribution in Europe. 
From Ross Island, in the Antarctic continent, Mr. Jas. Murray has quite 
lately brought back evidence of a considerable Rotatorian fauna, mostly 
Bdelloids, which he found living in large patches at the bottom and also on 
the surface of shallow lakes formed during the short summer period ; most 
of these are common forms in Europe, Africa, India, and elsewhere, but 
a few will be described, as new species. During the cold weather these 
Bdelloids contract into little balls and are frozen solid, but revive imme- 
diately the ice melts. Hydatina senta, a large and very cosmopolitan 
species, was found in abundance in one of the lakes on Ross Island. 
The very erratic appearance of rare or uncommon species in widely 
separated places seems to show that distance is no obstacle to their distribu- 
tion, provided only that they find suitable conditions. A few examples of 
such erratic distribution may here be cited :— 
Lrochosphera equatorialis was found by Semper in ditches which inter- 
sect rice fields in the Philippine Islands in 1859; its next appearance was 
in 1889 in Australia, where Gunson Thorpe found this same spherical Roti- 
fer in a pond of the Botanic Gardens in Brisbane; other examples were 
given. 
These examples of the occurrence of rare species of Rotifera in widely 
separated and distant lands will suffice to show the extreme range of distri- 
bution which these very minute but highly-organised animals have attained, 
and this in spite of the fact that they are essentially fresh-water forms and 
that the sea is to them an impassable barrier. 
As regards temperature it appears that, though the majority prefer a 
