292 Dr. J. H. Blasius oa the Diversity in the Estimate 



XXX. — On the Diversity in the Estimate of the European Ornis, 

 and its Causes. By Dr. J. H. Blasius*. 



It appears to me to be desirable that, from time to time, we 

 should ascertain the point which we have attained by our 

 joint endeavours. It is absolutely necessary that we should 

 ascertain clearly what we are to regard as positively gained, and 

 what we have to leave to the future as problems still to be 

 solved. Our circumstances, our environments indicate to us as 

 an important part of our endeavours the elucidation of European 

 ornithology. 



No land on the face of the earth has been more repeatedly 

 examined than Europe. AVe often hear, and, indeed, we might 

 justly suppose, that the ornithology of Europe is quite settled; 

 but every one who possesses an accurate knowledge of the sub- 

 ject must declare this assertion to be a manifest error. In no 

 branch of ornithology — neither in systematic division, nor in 

 literary criticism, nor in the observation of modes of life, nor in 

 oology — has complete agreement, certainty, or peace been arrived 

 at. To refer to one only of these points, that of the systematic 

 division and enumeration of species, — for nearly forty years, no 

 single scientific investigation, perhaps, has led to such divergent 

 results as this with regard to European ornithology. 



We find enumerated in— j^ t^e year Species. 



Brehm, ' Lehrbuch ' 1823 471 



Bonaparte, ' List,' &c 1838 503 



Temminck, ' Manuel,' 2ucl edit 1840 499 



Keyserling and Blasius, ' Wirbelthiere ' 1840 484 



Schlegel, ' Kritische Uebersieht ' 1844 489 



Thienemann, ' Rhea ' 1846 4/0 



Deglaml, ' Ornithologie ' 1849 507 



Bonaparte, ' Revue Critique ' 1850 539 



Brehm, ' Nauraannia ' 1855 950 



and with the subspecies Ifi28 



Brehm, ' Vogelfang' 18.55 1030 



and with the subspecies 1800 



Bonaparte, ' Catalogue Parzudaki ' 185(1 581 



De Selys-Longchamps, ' Revue de Zoologie' ... 1857 509 



Keitel, ' Vcrzeichniss,' &c 18.57 501 



Des Murs, ' Traite d'Oologie ' 1860 536 



* Tliis important pajjcr is translated from the Report of the Thirteenth 



