28 COLUMBID^. 



Subfamily COLUMBINE. 



The common Pigeons and Doves appear to be the least specialized 

 anatomically of the whole order, for they retain the ambiens 

 muscle, intestinal caBca, and oil-gland that so many of their allies 

 have lost. All have 12 rectrices. They exhibit considerable 

 differences and have been variously arranged, the true Doves of 

 the genus Turtur being generally placed in a distinct subfamily 

 from Columba, but there is no structural character of importance, 

 internal or external, by which the two can be separated. 



Keif to the Genera. 



a. Tail less than wing in length. 



a 1 . Neck-feathers not acuminate, dark bars 



on secondaries COLUMBA, p. 28. 



b'. Neck-feathers acuminate, no dark bars 



on secondaries DENDROTRKRON, p. 32. 



b. Tail not longer than wing, but exceeding 



of it. 



c'. Larger, no white tips to tail-feathers ; 

 tarsus shorter than mid-toe without 

 claw. 

 a". A white bar, conspicuous beneath, 



across tail PALUMBUS, p. 34. 



b''. No white bar across tail ALSOCOMUS, p. 35. 



a'. Smaller ; white or grey tips to tail : 

 tarsus longer than mid-toe without 

 claw. 

 c". Sexes alike; 2nd and 3rd quills 



longest TURTUR, p. 39. 



d". Sexes different ; 1st and 2nd quills 



longest (ENOPOPELIA, p. 47. 



c. Tail longer than wing and much graduated. MACROPYGIA, p. 48. 



Genus COLUMBA, Linn., 1766. 



This is the typical genus of the Columbine order, and contains 

 the Rock-Pigeons or Rock-Doves and their allies. The Wood- 

 Pigeons have been alternately included in the genus, as in Salvadori's 

 Catalogue, and classed apart ; but the latter plan is here followed, 

 as according better with the generic arrangement adopted in other 

 orders. The division of this group of Pigeons into genera of equal 

 value is a difficult task, although simpler when only the Pigeons of 

 a restricted area need arrangement than when all the known 

 species require to be classified. 



In the genus as here defined the corneous portion of the bill is 

 slender, the soft basal part swollen above the nostrils, which are 

 linear and oblique ; the wings are long and pointed, 2nd quill 

 longest (except in C. rupestris, in which the 1st exceeds the 2nd), 

 1st much longer than 4th ; the tarsus is naked and longer than the 

 bill from the gape, and the feet are formed for walking, the toes 



