NOTES ON KMHRYOS 327 



E. varius, liowcver, wc find that, like tlie other s])ecies, the 

 coverts exceed the rectrices in length and develo})nient, 

 thongh the latter are present and more advanced than in the 

 other. 



The sacral cleft of the spinal tract is slightly wider and 

 longer in E. varius and extends heyond the sacral region for- 

 ward into the scapular area. In the newly-hatched })ird the 

 difference is a little more marked, the arms of the tract heing 

 narrower than P. siilphiiratus. In other pai'ticnlars the 

 pterylosis of the two ])irds is similar. 



