1878.] MR. J. H. GURNEY ON A SPECIMEN OF POLYBORUS. 231 



On the 27th of May, 1877, one of these birds unfortunately died ; 

 and on examining the skin of this specimen, which proved on dis- 

 section to be a male, I have noticed the following points. 



The wing measures 15*6 inches; but the ends of the primaries are 

 worn considerably, and except for this the measurement would, I 

 think, have exceeded 16 inches ; the length of the tarsus is 3'7, and 

 that of the middle toe s. w. 2"3 inches. 



I have had the opportunity of comparing these measurements with 

 those of four specimens of Polyborus tharus which have been kindly 

 lent to me by Messrs. Salvin & Godman, and with those of two 

 specimens in the Norwich Museum ; also with the measurements 

 given by Mr. Sharpe, at p. 32 of the first volume of his Catalogue, 

 of two others in the British Museum. 



Unfortunately in none of these eight examples is the sex recorded ; 

 but the result appears to prove that Polyborus tharus is subject to 

 considerable variation of size, which further investigation may show 

 to be incident, in part, to the different localities from which the 

 specimens have been obtained. 



The following are the measurements alluded to : — 



It will be seen from the above measurements that there is nothing 

 in the dimensions of the specimen which died at the Gardens to show 

 that it is not an abnormal example of P. tharus ; and although the 

 extraordinary paleness of the ground-colour of its plumage presents 

 a curious difference from the coloration of the same portions of 

 the plumage in P. tharus, the form and disposition of the markings 

 in great measure agree with those of that species in its immature 

 stage. 



The following notes refer to the details in which the pale specimen 

 agrees with the ordinary P. tharus in its immature stage : — The upper 

 part of the head, including the occipital crest, is decidedly darker 

 than the adjacent plumage ; the ear- coverts are whole-coloured and 

 of a castaneous tint ; the feathers of the throat and upper breast 

 have strongly marked longitudinal shaft-marks ; and similar shaft- 

 marks, but narrower and fainter, are perceptible on the lower breast 



