472 



CERTHIID^E. 



and some of them placed in very different families. The 

 affinity between the species of Certhia as now restricted and 

 some of the true Wrens is very evident, and on the other 

 hand, through several exotic genera, a transition may he 

 easily traced to the next family to he mentioned, the Sittidce. 

 Those ornithologists who unite Certhia, Sitta and the inter- 

 mediate genera in one family may be justified, but the 

 systematists who place the Treecreepers near the Wood- 

 peckers take a very erroneous view of the characters which 

 really determine the affinities of birds. The Picidce possess 

 no structural character in common with the Certhiid<e as a 

 whole which is not shared by many other families that no one 

 has ever thought of allying to the former, for the stiffened 

 tail-feathers are only found in some forms of the latter and 

 not generally. There is no doubt, it is true, of the two groups 

 having certain somewhat similar habits, but these do not go 

 far in classification. 



