LAWS OF VARIATION 131 



forcibly remarked, that certain malconformations very 

 frequently, and that others rarely coexist, without our 

 being able to assign any reason. What can be more 

 singular than the relation between blue eyes and deaf- 

 ness in cats, and the tortoise-shell colour with the female 

 sex ; the feathered feet and skin between the outer toes 

 in pigeons, and the presence of more or less down on 

 the young birds when first hatched, with the future 

 colour of their plumage ; or, again, the relation between 

 the hair and teeth in the naked Turkish dog, though 

 here probably homology comes into play ? With 

 respect to this latter case of correlation, I think it can 

 hardly be accidental, that if we pick out the two orders 

 of mammalia which are most abnormal in their dermal 

 covering, viz. Cetacea (whales) and Edentata (arma- 

 dilloes, scaly ant-eaters, etc.), that these are likewise 

 the most abnormal in their teeth. 



I know of no case better adapted to show the im- 

 portance of the laws of correlation in modifying im- 

 portant structures, independently of utility and, there- 

 fore, of natural selection, than that of the difference 

 between the outer and inner flowers in some Compo- 

 sitous and Umbelliferous plants. Every one knows the 

 difference in the ray and central florets of, for instance, 

 the daisy, and this difference is often accompanied with 

 the abortion of parts of the flower. But, in some Com- 

 positous plants, the seeds also differ in shape and 

 sculpture ; and even the ovary itself, with its accessory 

 parts, differs, as has been described by Cassini. These 

 differences have been attributed by some authors to 

 pressure, and the shape of the seeds in the ray-florets 

 in some Compositae countenances this idea ; but, in the 

 case of the corolla of the Umbelliferae, it is by no means, 

 as Dr. Hooker informs me, in species with the densest 

 heads that the inner and outer flowers most frequently 

 differ. It might have been thought that the development 

 of the ray-petals by drawing nourishment from certain 

 other parts of the flower had caused their abortion ; 

 but in some Compositae there is a difference in the seeds 

 of the outer and inner florets without any difference in 



