Mr. R. B. Sharpe's Catalogue of Accipitres. 233 



This difference of opinion between ornithologists who have 

 closely examined considerable numbers of these birds in the 

 skin, must probably be ultimately solved by those naturalists 

 who may hereafter have the opportunity of observing them in. 

 a state of nature, and especially when engaged in the process 

 of nidification or during the period when the sexes are to be 

 found in pairs. With reference to Mr. Sharpe's account of 

 M. gilvicoUis, it may be well to remark that there appears to 

 be a misprint in the measurements of the adult male, the 

 tarsus being given as 1*2, instead of 2'2. 



In connexion with the succeeding genus, Geranospizias, 

 Mr. Ridgway, in the work already cited, has (at p. 42) a very 

 curious observation, tending to show the near relationship of 

 this genus to that of Polyboroides, which it would seem in 

 great. measure to represent on the American continent. Mr. 

 Ridgway remarks that he has found in " an alcoholic speci- 

 men of G. carulescens" the tibio-tarsal joint "flexible both 

 backwards and forwards '''.... and this singular flexibility 

 of that joint .... "just as well developed in Geranospiza" 

 as in Polyboroides. It may here be well to remark that the 

 more southern species of this genus, to which Mr. Sharpe 

 assigns the specific name of " ceerulescens ," bears in Mr. Ridg- 

 way's work that of "gracilis," while the "G. niger" of Mr. 

 Sharpe is divided by Mr. Ridgway into two races (called by 

 him '^ varieties "), one of which he states to occur in tropical 

 America, south of Panama; and to this he applies the name 

 of " ccerulescens ," its prevailing colour being " bluish plum- 

 beous •" whilst to the other, which is found north of Panama, 

 and is of a " plumbeous-black " colour, he restricts the spe- 

 cific name of " niger." In regard to the coloration of these 

 two races Mr. Ridgway adds the following remark : — " Spe- 

 cimens from Panama are exactly intermediate between cceru- 

 lescens from Brazil and niger from Mexico.^' 



Mr. Sharpe speaks of the " young stage " of G. niger as 

 being especially distinguished from the adult by a conspicuous 

 white bar on the lower surface of tbe primaries ; but another 

 noteworthy distinction is the white colour of the forehead 

 and chin in the immature birds, which is exchanged for slaty 

 black in the adults. 



