IXTKOlilVl'loX. IX 



The number of species recognized in the present Catalogue is 

 458, besides 27 of a more doubtful character, which are more or less 

 fully referred to in the body of the work. 42 species are still 

 desiderata in the Collection. 1 1 have been described for the first time. 



As to the classification of Pigeons, I have experienced the same 

 difficulties as in that of the Parrots. It is a well known fact that the 

 Pigeons constitute a very homogeneous order, which does not admit 

 of division into easily definable or sharply defined groups. 



Dr. Garrod, in a paper " On some points in the Anatomy of the 

 Columbce" (P. Z. S. 1874, pp. 249-259), has attempted a classifica- 

 tion based on anatomical characters, such as the ambiens muscle, 

 the intestinal caeca, the oil-gland, and the gall-bladder, but with 

 the result of forming only the most heterogeneous assemblages : 

 thus Garpophaga and Lojaholcemus are separated from the Fruit- 

 Pigeons or Treronince, and united with the Phabince or Ground- 

 Pigeons, while among the Treronince, with Treron and Ptilopus, we 

 find Phhgcenas, Starnoe.nas, Geopelia, and Goura ! 



I think that, for the present, the safest and most natural mode of 

 arranging them is offered by their external characters, and I propose 

 a system which is not very different from those propounded in 1872 

 by Sundevall (Meth. nat. Av. disp. Tentamen, pp. 97-101) and 

 in 1880 by Sclater ('Ibis,' 1880, pp. 406, 407). 



Owing to the want of a recent general Catalogue or Monograph 

 my task has not been easy ; and much of the good that may be 

 found in my work is owing to the help I have received from many 

 friends, especially Mr. Salvin, with whom I worked out the whole 

 of the American species, Dr. Sharpe, Dr. Sclater, Mr. Seebohm, 

 Prof. Newton, Dr. Oustalet, Dr. Eeichenow, and Graf von Berlepsch. 

 I have also to thank Canon Tristram, Mr. Eidgway and the 

 Authorities of the Smithsonian Institution, Mr. Allen, Dr. Hart- 

 laub, Dr. Finsch, Dr. Meyer, Mr. AViglesworth, Prof. Barboza 

 du Bocage, Dr. Schauinsland, Dr. W. Blasius, the Hon. W. Kothschild, 

 Mr. Hartert, and the Authorities of the Museums of Frankfort 

 and of Milan, for the loan of interesting specimens or for useful 

 information. 



T. SALVADOKI. 



Turin, Zoological Museum. 

 June 1893. 



