AMALGAMATIONS, INTENSION. 211 



The possible combinations of the ten varieties in question, any one 

 of which is as likely to occur as is any other, are 1,024, which is equal 

 to 2 raised to the loth power; the probability, therefore, that the com- 

 bination or set of varieties that succeeds in one district is ^, or i in 

 1,024; while the probability that those that succeed in the one district 

 will not be all the same as in the other will be J-^, or 1,023 m I > 2 4 

 which is more than a thousand times greater than the reverse prob- 

 ability. 



These 1,024 different results, any one of which may occur in one 

 section, are calculated on the supposition that all the representatives 

 of the species in one section that succeed in propagating will in time 

 coalesce by intercrossing; as we shall presently see, the number of 

 divergences in the two sections may be vastly increased by the diver- 

 sity of ways in which the same varieties may be combined through the 

 greater or less influence of minor segregations within the bounds of 

 each district. 



10. Amalgamational Intension. 



In my paper on ' ' Divergent Evolution through Cumulative Segre- 

 gation," I have referred to the fact that the vast majority of diver- 

 gent forms produced by segregation, after existing for a time, are 

 interfused with competing forms of the same species. Now, it is 

 evident that when a permanent segregation arises, if in the separate 

 sections there is a diversity of amalgamations between the slightly 

 divergent forms produced by partial segregations, the results will be 

 divergent in these separate sections. That there will be diversity in 

 this respect, we may argue, first, from the improbability that all the 

 varieties in any one section will occur in each of the other sections; 

 Second, from the improbability that if the same varieties occur in each 

 section they will occur in the same proportions; and, third, from the 

 improbability that if they are the same and in the same proportions, 

 they will break over the barriers and breed with each other in 

 precisely the same way in each section. Amalgamational intension 

 relates only to the last point. The other two points have been dis- 

 cussed under the principle that separation always involves more or 

 less segregation (see the third paragraph on the first page of this 

 paper), and under indiscriminate elimination, which we have just been 

 considering. 



Taking up, again, the supposed case considered under eliminational 

 intension, if the different kinds of new food were so situated as to 

 make it more or less difficult for those feeding on one kind to cross 

 with those feeding on other kinds, the representatives of the species in 

 each of the completely separated districts would be divided into minor 



