EVOLUTIONARY TELEOLOGY. 3S3 



Let us learn from tlie same writer how both eved 



ft. 



of the flomider get, quite unintentionally, on the Bume 

 side of the head. The writer makes much of this case 

 {see p. 3Y2), and we are not disposed to pass it by : 



"A similar application may be made to the PleuTonect'i. 

 Presmnablj, these fishes had adopted their peculiar mode of 

 swimming long before the position of their eyes became adapted 

 to it. A spontaneous variation occurred, consisting in the pas- 

 sage of one eye to the opposite side of the head ; and this varia- 

 tion afforded its possessors such increased facilities of sight tbat 

 in the course of time the exception became the rule. But the 

 remarkable point is, that the law of heredity not only preserved 

 the variation itself, but the date of its occurrence; and tliat, 

 altliough for thousands of years the adult Pleuronecta have had 

 both eyes on the same side, the young still continue during their 

 earlier development to exhibit the contrary arrangement, just 

 as if the variation still occurred spontaneously." 



Here a wonderful and one would say miaccountaljle 

 transference takes place in a short time. As Steen- 

 strup showed, one eye actually passes through the 

 head while the young fish is growing. AVe ask how 

 this comes about ; and we are told, truly enough, that 

 it takes place in each generation because it did so in 

 the parents and in the whole line of ancestors, Why 

 offspring should be like parent is more than any one 

 can explain ; but so it is, in a manner so nearly fixed 

 and settled that we can count on it ; yet not from any 

 absolute necessity that we know of, and, indeed, with 

 sufficiently striking difference now and then to demon- 

 strate that it might have been otherwise, or is so in a 

 notable degree. This transference of one eye througli 

 the head, from the side where it would be nearly use- 

 less to that in which it may help the other, bears all 



