AND INDIVIDUALS. 277 



run through all animals, and the characters of the Vertebrate 

 type, and the Bird features of their external conformation, there 

 are the characters which unite them in the little group called 

 the Song-sparrow group. But now, in regard to the latter case, 

 how many different kinds of Song-sparrows are there ? Some 

 say four or five, and others say seven ; and even the same author 

 is in doubt to a certain extent. If the seven so-called species 

 can be reduced to four, then there are three of them which must 

 have arisen from a common parentage with certain ones of the 

 four ; but if the seven are really distinct, then each had a sepa- 

 rate parent. Now these closely related specific diversities are 

 more or less such as may be exhibited even in the same nest ; 

 and it is on this account, and with the knowledge of these facts, 

 that a large number of naturalists have argued that the diversi- 

 ties among the different species have originated from a com- 

 mon parentage ; and since, too, they have observed that the 

 group of Song-sparrows are more or less intimately related to 

 the Chipping-sparrows or Buntings, and in fact cannot be sepa- 

 rated from them by any definite line, they refer the two groups to 

 some primeval parentage; and so they go on linking, by this 

 method of comparison, one group of birds with another, in vari- 

 ous degrees of relationship, until the whole class of Birds is 

 referred to one typical feathered creature. 



But now comes the question as to the relation of the typical 

 bird to the other classes, the Mammals on the one hand, and the 

 Reptiles and Fishes on the other. I have already spoken of the 

 transition from the Fishes to the Reptiles in the instance of the 

 Lepidosiren (p. 263) ; and now I have to present in regard to the 

 Birds another just as remarkable case of relationship. . There 

 has recently been discovered in the lithographic stone region 

 of Germany a vertebrate, fossil animal, which combines such a 

 set of characters in its skeleton, and the impressions of its 

 feathers, as to induce in those who have seen it the same diver- 

 sity of opinion in regard to its relations as was done in the 

 case of the Lepidosiren. On the one hand, a certain German 

 naturalist pronounced it a bird; but another characterized it as a 



