TO BIRD-ANATOMY AND CLASSIFICATION. 



211 



Ibis, 1881, 

 p. 29. 



any combination of these characters that could lead to its inclusion with Ibls 

 the three combinations present in the Anomalogonatae. 



The grand division into Homalo- and Anomalogonatap was primarily 

 made by Mr. Garrod on the strength of the facts here tabulated. But 

 subsequent investigations of quite different points have much strengthened 

 his original position. One of these is the difference in distribution of 

 the plantar tendons in the two groups of zygodactyle birds, already 

 described above. 1 believe the removal of the Cuculidae and Musopha- 

 gidae from the so-called "Picarian" birds, or " Coccygomorphae," on 

 account of their possessing the ambiens muscle, absent in the others, was 

 considered by many naturalists a striking proof of the artificial nature of 

 Prof. Garrod's system. But it has been most remarkably confirmed by 

 his later discovery, and so is, to my mind, one of the most convincing 

 proofs of the correctness of his arguments, until, at least, some other 

 explanation shall be given of the facts here adduced. Yet another con- 

 firmation is afforded by the pterylosis. I here reproduce Prof. Garrod's 

 own words : " My study of pterylography has led me to look upon the 

 nature of the dorsal tract as all important in determining to which great 

 group of birds, the Homalogonatae or Anomalogonatse, any doubtful 

 family belongs. When the dorsal tract develops a fork between the 

 shoulders, a bird is Homalogonatous ; when the tract runs on unenlarged 

 to near the lower ends of the scapulae, then it is Anomalogonatous " 

 (P. Z. S. 1878, p. 931). 



* In Monnotus the tuft is absent. 



