DEVELOPMENT BY SMALL STEPS. 22? 



illustration, and I select for this purpose an exam- 

 ple frequently used the whalebone in the mouth 

 of the Greenland whale. This organ consists of a 

 large number of long horny plates, hanging down 

 from the front of the palate on either side of the 

 mouth. They form two longitudinal series of plates 

 very close together. The inner edges of the plates 

 are frayed into a hair-like fringe, and the whole 

 forms a sort of sieve at the sides of the mouth. 

 When the whale feeds, he opens his mouth widely, 

 taking into it quantities of water, together with 

 many small animals, which form his food ; and then 

 closing his mouth, the water is forced out through 

 this sieve of baleen plates. The water readily passes 

 through them, while the animals are retained in the 

 mouth, and are now swallowed. The beauty of this 

 contrivance is evident at once, enabling the animal 

 as it does to feed upon small food under water. 

 After it has once become perfected enough to be 

 thus used, it is easy to see that natural selection 

 could cause its preservation. But the question is, 

 how such an organ could have arisen by small 

 stages, since it would obviously be of no use until 

 the plates became long enough to serve as a sieve ; 

 and there must have been a very long time, while 

 the organ was developing, when it would not be large 

 enough to serve in this way, and was yet preserved. 

 How such an organ, or any similar organ, useful only 

 when highly developed, could have been started on 

 its line of development upon this theory, it is diffi- 

 cult to see, for it would seem that at first the vari- 

 ations would have been of no use, and consequently 

 not under the influence of natural selection. 



