Eyelids and Lachrymal A pparatus of Birds. 
5 
semble thick/ coarse hairs, and this resemblance to vertebrate cilia 
is all the more pronounced in that these filiform feathers are in- 
serted at the outer border of the lid margin (sometimes within 
the intermarginal space) in several irregular rows, which at a few 
points interlace with the lashes (feathers) of the opposing lid. 
Moreover, when the lids are closed the inner lid-margins roll in 
more than is the case with the Sparrow, so that the intermarginal 
spaces come closer together, although their entire surfaces do not 
touch, as in Man. 
These feather-eyelashes belong to the class of filoplumes, or 
thread leathers with no true vanes, thirty to thirty-five in number, 
Fig-. 2 — External Eye of the African Ostrich — Struthio camelns. (Wood 
and Slonaker. ) 
more being found in the upper lid than in the lower. Of mam- 
observations the writer found the average proportion to lie 1 1 to I I. 
In most instances the plumule of the tuft rises just above the soft 
margin of the eyelid and is bent or directed away from the anterior 
canthus toward the back of the head, parallel to a line joining the 
two canthi. The plumules do not meet or form a screen over the 
palpebral margins or the interpalpebral space, as in the Ostrich or 
in Man. In some individuals the tufts are entirely wanting or are 
inserted irregularly some distance from the margin of the lid. 
