130 THE ZOOLOGIST. 



is no doubt due to the impossibility of seeing it from below, and 

 to a certain extent to an omission which is very frequently made 

 in natural history, namely, that only a few forms of a supposed 

 group are examined, and that conclusions about the whole group 

 are made from such scanty observations ; from the nature of the 

 point in question, which served to characterize the groups, a 

 certain species is afterwards classified, and thus an everlasting 

 circulus vitiosus is entered. 



The removal of the under wing-coverts cannot have caused 

 the mistake, as the first primary in most cases where it has been 

 supposed to be absent is lying somewhat above the first func- 

 tionary long primary, hidden by and somewhat assimilated to 

 the primary coverts. 



