5IO 



SHUFELDT. 



[Vol. XVII. 



four sternal, and one almost sternal pair of ribs, because their 

 fifteenth or first anchylosed vertebra (instead of the sixteenth 

 or second anchylosed vertebra) carries the first pair of sternal 

 ribs." 



It is very likely that Didiinculus strigirostris is as nearly 

 related to the genus Cohmiba as it is to any other one of the 

 minor groups of pigeons. 



Concluding Remarks. 



Since this memoir was presented for publication in the 

 winter of 1899, an important work upon birds has appeared. 

 I refer to the Hand-List of Birds compiled by Dr. R. Bowdler 

 Sharpe, for a copy of which I have to thank him and the 

 trustees of the British Museum. In Vol. I of that excellent 

 work (pp. 51-92) we find upwards of six hundred species of 

 existing pigeons enumerated, and not a few extinct forms. As 

 a group, Dr. Sharpe places this large assemblage of birds next 

 after the Pteroclidiformes (Order IV) and immediately before 

 the Opisthocomiformes (Order VI), and classifies them as 

 follows: 



Order (V). 



Suborders. 



Families. 



r 



I. Columbiae. -^ 



I. TreronidcB. 



Columbidae. 



3. Peristeridae. < 



Subfamilies. 



1. Treroninae. 



2. Ptilopodinae. 



3. Carpophaginas. 



4. Columbinae. 



5. Macropygiinas. 



6. Ectopistins. 



7. Zenaidina;. 



8. Turturinae. 



9. Geopeliinas. 



10. Peristerinas. 



11. Phabinae. 



12. Geotrygonirice. 

 ^ 13. Caloenadinae. 



Didi. 



4. Gouridae. 

 i^ 5. Didunculidcc. 

 6. Dididae. 



All the forms in the second suborder of this arrangement 

 are now extinct, including as it does only the two genera 



