ORIGIN AND CHARACTERISTICS 51 



of syrinx intermediate between this type and 

 the next peculiar to certain Cuckoos and Owls. 

 The third type is the normal one, including the 

 Singing Passeres, its principal features having 

 already been described. Here we may say that 

 the tongue in no way assists the voice in 

 birds ; with the possible exception of Parrots in 

 captivity. 



Summarising Professor Fiirbringer's con- 

 clusions respecting the origin of birds, he 

 commences with the supposition that they com- 

 menced their descent as toothed forms of small 

 or moderate size, with long tails and four feet 

 similar to those of a lizard, their bodies clothed 

 with a primitive sort of down. These were 

 succeeded by creatures in which the down had 

 become feathers and the fore limbs had become 

 prehensile organs, the hinder limbs chiefly used 

 for progression ; these modifications being corre- 

 lated with a transformation of the legs and 

 pelvis and a fusion of the metatarsals, resulting 

 in a flightless feathered biped. The feathers not 

 only now began to increase in size and stiffness, 

 but various modifications of the skeleton and 

 the muscles eventually endowed these early 

 avine forms with the power of flight. The two 

 species of Archa^opteryx are all that remain to 



