Systematic Position of Zeledonia coronata. 9 



distinctly from that in the Turdidse, and can be distinguished 

 even in the embryo. Even where fusion is taking place it 

 would always be possible to distinguish the acrotarsium of 

 the one group from that of the other by counting the number 

 of disappearing elements. 



Planta.' — By the backward extension of the outer border 

 of the acrotarsial shield this forms a knife-like edge. The 

 inner side of this is clothed by a long narrow plate. 



Claws. — These are not conspicuously large, that on the 

 hallux being the largest. 



General Remarks on the Pterylosis of Zeledonia and of the 

 Turdidse in general. 



In its pterylological characters Zeledonia, so far as I have 

 been able to discover, agrees more nearly with the Turdidse 

 than with any other group. 



But what are, precisely, the pterylological characters of 

 the Turdidse? Unfortunately, owing to lack of material, 

 I cannot at present say, nor can I find any scientific con- 

 tribution to this subject. So much, however, seems apparent, 

 that the Turdidse, as a group, present certain common 

 characters, which may be regarded as distinctly Turdine. It 

 is possible, however, that these distinctions, which are of a 

 somewhat subtle description, will break down when the 

 pterylosis of the Timeliidse (revised), Pycnonotidas, Alaudidse, 

 Motacillidse, Mniotiltidse, and Sylviidse — of Dr. Sharpe's 

 ' Hand-list ' — come to be studied. These several " families " 

 will, I believe, prove to be more closely related than has 

 been supposed. 



Among the Turdidse the spinal tract is found to assume 

 two distinct forms — (a.) in which pteryla spinalis runs down 

 the back as a broad band, and (/3) where it expands in the 

 lumbar region into a diamond-shaped patch. 



Since, however, the same features obtain in other families 

 of Passeres, the form of this tract can have but a limited 

 value for the systematist. But it promises to be of some 

 use in determining the generic distinctness or otherwise of 

 allied species. To take a case in point, Merula merula differs 



