first cousins the reptiles, and of some other animals, there projects 
into the vitreous to the posterior aspect of the lens (or nearly so) 
a remarkable, pigmented, corrugated or plicated, solid or fenestrated, 
erectile body long known as the pecten, marsupium or “ruff.” It is 
composed of large vascular trunks, about which are arranged 
smaller vessels with cellular walls—all bound together loosely by 
connective tissue and covered with a smooth, thin, homogeneous, 
pigmented membrane. Treacher Collins regards the pectinate body 
as a prolongation of the chorioid (which it resembles structurally), 
containing, however, a finer capillary plexus. Most authors, in- 
Fig. 2.—Section of the eye of the Golden-winged Woodpecker, showing espe¬ 
cially the folds of the pecten, the ring fibers of the lens and nictitating membrane. 
eluding Gegenbaur and Bernd ; believe that it takes the place of the 
retinal vessels (which, in the avain fundus, are wanting), and arises 
from the optic tissues, having no direct connection with the chori¬ 
oid. By this arrangement the percipient part of the bird’s retina 
is rendered more sensitive to light rays, because the branches of the 
central artery and vein do not ramify, as in the mammals, in the 
substance of the retina, and so do not, to any extent, present an 
opaque obstruction to vision. 
The pecten varies in shape and size, as well as in the number (2 
to 30) and the character of the folds of tissue that compose it. 
