296 Dr. J. H. Blasius on the Diversitij in the Estimate 



Falco peregrinoides, T. Troglodytes fumigatus, T. 



sparverius, L. Uragus sibiricus. Pall. 



Haliaetus leucocephalus, L. Corvus dauricus, Pall. 



Ulula nebulosa, Forst. ossifragus, fVils. 



Caprimulgus atrovirens. Laud. Peristera semitorquata. Gin. 



climacurus, Vieill. liigens, Riipp. (risoria, L.). 



virginicus, Briss. Eurynorhynchus pygmteus, L. 



Hirundo senegalensis, L. (ca- Ardea herodias, L. 



pensis, Gm.). Buphus russatus, T. 

 Parus atricapillus, Gm, Pelecanus mitratus, Lieht. 

 bicolor, L. Dysporus melanurus, T. &c. 



It would be a just requirement of tlie ornithological public 

 from its writers, or of the latter from themselves, that they 

 should only admit positively ascertained species into the fauna 

 of Europe, and finally consign ascertained errors to oblivion. 

 This certainly does not offend against any internal conviction, 

 or against a principle carried out to its consequences. The 

 question regards only a vacillation between a mere external 

 scrupulous completeness in name, or simple, non-critical care- 

 lessness, and positive adherence to fact. 



It is only when we remove the whole of the exotic species, or 

 at least those which have been erroneously admitted, that we 

 can see clearly how far the different numbers of the summary 

 above given are caused by diversity of fundamental views, by 

 mutually opposed principles or requirements. 



If we deduct the whole of the exotic species observed occa- 

 sionally in Europe, there remain in 



Thienemann, ' Rhea ' 401 species 



Keyserling and Blasius, ' Wirbelth.' 424 ,, 



Schlegel, ' Krit. Uebersicht ' 430 



Brelim, ' Lehrbuch ' 450 „ 



Bonaparte, ' Revue Crit.' 463 „ 



Des Murs, •' Traite ' 466 



Bonaparte, ' Catalogue P.' 500 „ 



Brehm, ' Vogelfang ' 940 „ 



and with the subspecies 1700 „ 



as regular inhabitants of Europe. There is no essential change 

 in the proportions above given ; the statements vary from double 

 to quadruple the average number. Here also occurs again the 

 same abrupt and irreconcileable opposition of the majority of 



