Page:The Zoologist, 4th series, vol 3 (1899).djvu/154

130 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 functionary long primary, hidden by and somewhat assimilated to the primary coverts.