Contributions to Bird- Anatomy and Classification. 15 



as well as the fact that this diversity of type exactly coin- 

 cides with the two groups of birds so marked out being re- 

 spectively ^'Homalo-" and "AnomalogonatousJ" Thus^ in the 

 Parrots, Cuckoos, and Musophagidse, which are all Homalo- 

 gonatous, possessing (at least typically) the ambiens muscle, 

 the plantar tendons are distributed in exactly the same 

 way as in the common Fowl, the fiexor perforans supplying 

 digits ii-iv, and the fi^exor hallucis digit i alone (neglecting 

 the vinculum). In all the Anomalogonatous zygodactyle 

 birds (which all lack the ambiens and accessory femoro- caudal 

 muscles), namely the Picidse, Capitonidse, and their allies, 

 Bucconidse and Galbulidse, an entirely unique arrangement 

 is found ; for in those birds the flexor longus hallucis splits up 

 into three parts, supplying digits ii and iv as well as the 

 hallux, whilst the flexor perforans digitorum is distributed to 

 the third digit alone. These differences in the two types will 

 be clearly seen by comparing fig. 8 {Crotopliaga sulcirostris] 

 and fig. 9 [Megalcema asiatica) . 



Fiff. 8. 



Foot of Crotophaga sulcirostris. Foot of Megcdcema asiatica. 



(From P. Z. S. 1875, p. 346, figs. 7 & 8.) 



