



LOTSY, CHARLES DARWIN OVER DEN INVLOED DER KRUISING. 541 
the European races, than the latter do with each other. In Ger- 
many the female spitsdog is said to receive the fox more readily 
than will other dogs; a female australian Dingo in England attracted 
the wild male foxes. But these differences in the sexual instinct 
and attractive power of the various breeds may be wholly due to 
their descent from distinct species. In Paraguay the horses have 
much freedom, and an excellent observer (RENGGER Säugethiere 
von Paraguary 1336) believes that the native horses of the same 
colour and size prefer associating with each other, and that the 
horses which have been imported from Entre Rios and Banda 
oriental into Paraguay likewise prefer associating together. 
In Circassia six sub-races of the horse have received distinct 
names; and a native proprietor of rank (see: L’HERBETTE and 
DE QUATREFAGES, in Bull. Soc. d’ acclim. t. VIII July 1861 p. 312) 
asserts that horses of three of these races, while living a free life, 
almost always refuse to mingle and cross, and will even atiack 
one another. 
It has been observed, in a district stocked with heavy Lincolnshire 
and light Norfolk sheep, that both kinds, though bred together, 
when turned out „in a short time, separate to a sheep” :the Lincolns 
drawing off to the rich soil, and the Norfolks to their own dry 
soil; and as long as there is plenty of grass „the two breeds keep 
themselves as distinct as rooks and pigeons”. In this case different 
habits of life tend to keep the races distinct. On one of the 
Faroe islands, not more than half a mile in diameter, the half- 
wild native black sheep are said not to have readily mixed with 
the imported white sheep. It is a more curious fact that the 
semi-monstrous ancon sheep of modern origin „have been observed 
to keep together, separating themselves from the rest ofthe flock, 
when put into enclosures with other sheep” (Phil. Transact. 1813 p. 90). 
With respect to fallow-deer, which live in a semi-domesticated 
condition, Mr. BENNETT states that the dark and pale coloured 
herds, which have long been kept together in the Forest of Dean, 
in High meadow woods, and in the New Forest, have never been 
known to mingle: the dark-coloured deer, it may be added, are 
believed to have been first brought by JAMES | (dus reeds in de 
16e eeuw) from Norway, on account of their greater hardiness. 
I imported from the island of Porto Santo two of the feral rabbiis, 
