334 Mr. Vigors's Sketches in Ornithology. 



The true 



Milvus, Auct. 

 is distinguished from the last genus by the fourth quill feather 

 being the longest, by the acrotarsia being scutellated, and the 

 exteriour toe united to the middle by a membrane. It contains 

 the European species, M. ictinus, Sav. (F. Milvus, Linn.) and 

 F. ater, Linn. Although the species of this genus are noted for a 

 feeble bill, it may be observed that it is not so much bent at the 

 base, as in the typical species of the family, but exhibits somewhat 

 of the length and straightness that characterize the bill of the 

 Eagles. Some of the extremes of these last birds are found to 

 approach the present stirps also inform and organization. The 

 whole of those which in South America are known under the name 

 of Caracara, from their singular cry, and which are included in the 

 earliest genera of this arrangement, present a bill much weaker 

 than that of the typical Eagles, and nearly meeting the bill of the 

 Kites. We find indeed that the type of the genus Polyborus was 

 described by Ray as Milvus Braziliensis,* and with similar deno- 

 minations by others of the earlier writers : nor has the affinity been 

 less noticed by our later naturalists. +1 do not, however, feel suffi- 

 ciently satisfied with respect to the immediate affinities by which 

 these two stirpes are connected. We know too little of the birds 

 that form the extreme groups of the Eagles to speak of them with 



* Milvus Braziliensis, Caracara dictus. Ray. Syn. Method. Av. p. 17. M. 

 Brisson calls this bird Circus Braziliensis. 



+ M. Temminck has pointed out this affinity of the Caracaras to the Kites, 

 as well as that which they exhibit to the Vultures ; at the same time stating 

 the difficulty which these double affinities impose upon him. " II se presente 

 quelques difficultes dans cet arrangement : elles naissant des formes exteri- 

 eures de ces Caracaras, qui les associent aux Milans et aux Buses, ainsi que 

 du choix decide que certaines especes montrent sur les charognes ; ce qui les 

 rapprocherait des Vautours et des Cathartes, s'ils n'etaient en meme temps en- 

 tomophages, et reptilivores." Temm. Art. Falco aterrimus, PI. Col. 37. We 

 have already seen how these groups preserve their affinities at once to the Vul- 

 tures, the Eagles, and the Kites. It is one of the greatest beauties of that cir- 

 cular disposition which is so generally observed to prevail throughout nature, 

 that it removes those difficulties that stand in the way of the naturalist, and 

 explains those apparent anomalies, that would otherwise tend to interrupt his 

 progress. 



