386 Scientific Intelligence 2*oology. 
other species, had already convinced him, that it also belonged 
to the same tribe ; and was consequently an animal in a perfect 
state. Sir Everard Home obtained from Mr Bullock several 
specimens, having the organs of generation in a developed state, 
brought from a lake three miles from the city of Mexico. The 
temperature of the lake is never below 60°, and its elevation a- 
bove the sea is 8060 feet. In the month of June, the protei are 
so abundant in it, as to form a principal part of the food of the 
peasantry. In the plates accompanying the memoir, the female 
organs, in their developed state, are well seen, and there is strong 
probability, from the appearance of the ova contained within 
them, that they pass out singly. 
30. Migration of Birds . — Dr Schinz, secretary to the Pro- 
vincial Society of Zurich, has endeavoured to discover the laws, 
according to which the birds of Europe are distributed over our 
Continent. The country in which the bird produces its young 
is considered as its proper one. The nearer we approach the 
Poles, the more do we find peculiar or stationary birds, and the 
fewer are the foreign species which make their appearance. 
Greenland has not a single bird of passage. Iceland has only 
one, which remains during winter, and leaves it in spring, for 
still more northern countries. Sweden and Norway have already 
more birds of passage, and we find them increasing in number, 
in proportion as we advance towards the centre of Europe. In 
the intertropical countries no bird emigrates ; to the north they 
all emigrate. The propagation of birds keeps pace with the 
quantity of food. Spitsbergen has but a single herbivorous 
species; for the sea presents more nutriment, and all the rocks and 
cliffs are inhabited by aquatic birds. In the frigid zone, a much 
greater number of marsh birds breed than beyond the Arctic 
Circle, and in the warm countries of Europe. Dr Schinz also 
indicates the distribution of the species of domestic fowls ; and 
remarks, that each country has its peculiar varieties of fowls, 
— . Bulletin Universel. 
31. Wolves in Livonia . — According to a report recently ad- 
dressed to the Regency of the Government of Livonia, the wolves 
have, for some time back, made dreadful ravages in that pro- 
vince. In the year 1823, they devoured 845 horses, 1243 foals, 
