THE PEOBLEM OF UTILITY. 495 



botanists as follows : — Are there any examples within your know- 

 ledge of well-marked varieties (not mere individual states due to 

 local conditions) which occupy a considerable area to the ex- 

 clusion of the parent species, and which do not occupy auy area, 

 or only a very small one, with the type ? Each of them suggested 

 several species which seemed to answer to the conditions, but 

 on further consideration it appeared that they did not do so, and 

 we were finally reduced to a single case, that of one of the species 

 of Hubus, a genus which most botanists will regard as a very 

 unsafe one to draw any conclusions from. Huhus radula, Weihe, 

 is said to be abundant in the Midland parts of England, but in 

 the Southern and South-western counties to be replaced by the 

 variety anglicanus of W. M. Rogers, the type never having been 

 found in the area occupied by this variety. If this is the case, 

 and the two forms, said to be easily recognizable, really occupy 

 distinct areas and. nowhere overlap, or very slightly so, then we 

 have the condition precedent to the formation of a species by the 

 extinction of the type, thus leaving the variety to represent the 

 species. Of course in this case we do not know that the characters 

 which distinguish the variety are useless ; but if they are so, 

 and if the variety should possess some superior vigour of con- 

 stitution or other useful peculiarity which enables it to survive 

 when the type dies out, we should have an illustration of one mode 

 in which useless specific characters may possibly have arisen. 



The enquiry is interesting, however, because it brings to light 

 the rather unexpected fact, that fixed varieties of plants occupy- 

 ing considerable areas to the exclusion of the type are not 

 common, and, perhaps, in our island do not exist. And should 

 they be found to occur more frequently in other countries — as 

 varieties of birds, mammals, and. reptiles do occur in separate 

 areas in North America — they may be usually explained as 

 adaptations to very diiferent climatic conditions, in which case 

 the distinguishing characters will be utilitarian, and the local 

 varieties will be really incipient species. 



The preceding enquiry leads us to certain very definite con- 

 clusions. In the first place, we see that species, which have been 

 differentiated as such by the laws of variation and survival of 

 the fittest, must be characterized by certain peculiarities whereby 

 they have obtained an advantage in the struggle with their 

 fellows. These peculiarities constitute their " specific characters," 



