330 Mr. J. H. Gurney's Notes on 



XXIX. — Notes on a 'Catalogue of the Accipitres in the British 

 Museum' bij E. Bowdler Sharpe (1874). By J. H. 



GURNEY. 



[Continued from p. 84] 



In considering the genera which are most nearly related to 

 the Milvine group in the restricted sense of that term^ and 

 which if it be taken in a wider sense may be included in it_, 

 I would in the first instance refer to the American genus 

 Elanoides, the sole species of which {E. furcatus), though 

 bearing a considerable resemblance in external appearance to 

 the Milvi of the Old World, possesses differences of structure 

 which indicate that its true position is that of an isolated 

 form, as has been pointed out by Mr. Ridgway, at p. 180 of 

 his ' Studies of the American Falconidse.^ 



I may add, with reference to this species, that its imma- 

 ture stage of plumage, which is not noticed in Mr. Sharpens 

 work, is described at page 192 of vol. iii. of Messrs. Baird, 

 Brewer, and Ridgway's ' History of North- American Birds.^ 



From Elanoides furcatus the transition is a natural one to 

 the little Nauclerus rioucouri of intertropical Africa, which 

 at first sight appears to be a miniature species of Elaiioides, 

 but which is in reality more closely related to the genera 

 Elanus and Gampsonyx. 



One remarkable point of agreement between the three 

 genera Nauclerus, Gampsonyx, and Elanus is the absence of 

 any groove on the under surface of the claws — a peculiarity 

 which has been pointed out by Mr. Ridgway in the article 

 above referred to. 



It is somewnat curious that the genera Nauclerus and Gam- 

 psonyx, like that of Elanoides, contain each but a single 

 species. 



In the case of Gampsonyx, as in that of Elanoides, the 

 differences between the immature and adult stages of plumage, 

 though not referred to by Mr. Sharpe, are very appreciable. 

 An immature example of G. swainsoni, from the Upper 

 Amazons, which is preserved in the Norwich Museum, diflFers 

 from the adult bird in the following particulars, viz. : — All the 



