HEREDITARY TRANSMISSION AND VARIATION. 99 



plished, I believe it is looked upon as a point of great 

 beauty. 



But here is the last great variety, — the Tumbler ; 

 and of that great variety, one of the principal kinds, 

 and one most prized, is the specimen represented here 

 — the short-faced Tumbler. Its beak, you see, is re- 

 duced to a mere nothing. Just compare the beak of 

 this one and that of the first one, the Carrier — I believe 

 the orthodox comparison of the head and beak of a 

 thoroughly well-bred Tumbler is to stick an oat into a 

 cherry, and that will give you the proper relative pro- 

 portions of the head and beak. The feet and legs are 

 exceedingly small, and the bird appears to be cpiite a 

 dwarf when placed side by side with this great Carrier. 



These are differences enough in regard to their ex- 

 ternal appearance ; but these differences are by no 

 means the whole or even the most important of the dif- 

 ferences which obtain between these birds. There is 

 hardly a single point of their structure which has not 

 become more or less altered ; and to give you an idea 

 of how extensive these alterations are, I have here some 

 very good skeletons, for which I am indebted to my 

 friend Mr. Tegetmeier, a great authority in these mat- 

 ters ; by means of which, if you examine them by-and- 

 by, you will be able to see the enormous difference in 

 their bony structures. 



I had the privilege, some time ago, of access to 

 some important MSS. of Mr. Darwin, who, I may tell 

 you, has taken very great pains and spent much valu- 

 able time and attention on the investigation of these 

 variations, and getting together all the facts that bear 

 upon them. I obtained from these MSS. the follow- 

 ing summary of the differences between the domestic 



