68 THE FOUR SEGREGATIVE PRINCIPLES. 
According to the New Orleans Times-Democrat* there are on the 
shores of Louisiana, near the mouth of the Mississippi river, two types 
of cats. The great majority are like the cats of other regions, but a 
small tribe on Tarpon Island have apparently lost all aversion to being 
in the water. Their separation from other families of cats has allowed 
of their establishing their habits of feeding on entirely new lines of 
tradition, for they all wade freely in the shallow waters of the beach 
hunting for small fish; and three or four of the bolder ones swim off 
to oyster boats lying at anchor near by. ‘This is an example of parti- 
tion allowing an innovation to be established through election as a 
permanent habitude; and as Captain Bosco, who owns these cats, 
says it is many years since they began to go into the water, we have 
reason to believe that coincident selection has begun to operate in 
producing a breed whose innate instincts are better adapted to this 
mode of life than were those of the original stock from which they 
sprang; or may it not be possible that the direct inheritance of ac- 
quired characters has removed the instinctive aversion to water that 
belongs so universally to cats? If, now, after the habits and innate 
instincts of the new breed are well established, several pairs of them 
should be taken to a part of the shore where other cats possessing 
the usual instincts of the species are found, it is possible that their 
special endowments and social habits might lead them to associate 
with each other, and thus to perpetuate the habits already formed, 
and to breed with each other. If such should be the case, it would be 
an example of social and industrial partition, leading to discriminate 
isolation and tending to produce permanent segregate breeding. As, 
however, the segregative social instincts of the cat seem to be weak 
compared with those of most mammals, the opportunity for establish- 
ing separate races of cats is not as good as in the case of most domestic 
species. 
14. Cooperation of Structural Isolation and Structural Selection Illustrated. 
The correlation that may exist between a given form of isolation and 
the corresponding form of selection is seen in the case of the different 
forms of impregnational isolation and impregnational selection. Let 
us consider the case of two varieties of the same species of land snails 
that are prevented from crossing by the fact that in one variety the 
sexual organs are on the right side of the body (the male organs 
being near the head and the female organs a little further back), 
while in the other variety they are arranged in the same way on the 
* New Orleans Times-Democrat, probably January, 1900, as it was copied by a 
Philadelphia paper late in January, 1900. 
