THE INTRODUCTION OF NEW SPECIES. 23 



jections exist against every theory on such a subject, 

 but this is not necessarily the case. The hypothesis 

 put forward in this paper depends in no degree 

 upon the completeness of our knowledge of the 

 former condition of the organic world, but takes 

 what facts we have as fragments of a vast whole, 

 and deduces from them something of the nature and 

 proportions of that whole which we can never know 

 in detail. It is founded upon isolated groups of 

 facts, recognizes their isolation, and endeavours to 

 deduce from them the nature of the intervening 

 portions. 



Rudimentary Organs 



Another important series of facts, quite in accord- 

 ance with, and even necessary deductions from, the 

 law now developed, are those of rudimentary organs. 

 That these really do exist, and in most cases 

 have no special function in the animal oeconomy, 

 is admitted by the first authorities in comparative 

 anatomy. The minute limbs hidden beneath the skin 

 in many of the snake-like lizards, the anal hooks 

 of the boa constrictor, the complete series of jointed 

 finger -bones in the paddle of the Manatus and 

 whale, are a few of the most familiar instances. In 

 botany a similar class of facts has been long re- 

 cognised. Abortive stamens, rudimentary floral en- 

 velopes and undeveloped carpels, are of the most 

 frequent occurrence. To every thoughtful naturalist 

 the question must arise, What are these for ? What 

 have they to do with the great laws of creation? 



