86 TYPES OF ANIMAL LIFE 



is a minute fold of skin which serves no known purpose 

 whatever, but is the representative of the bird's third 

 eyelid or "nictitating" (that is winking) membrane. A 

 truly wonderful mechanism also exists in connection with 

 this membrane. It is drawn over the eye by the aid 

 of a muscle with a delicate tendon, which sweeps round 

 the nerve of sight (the optic nerve), and would injuri- 

 ously compress it were it not that, on its way, it passes 

 through a loop-like tendon belonging to a distinct 

 muscle, which, acting at the same time, pulls it suffici- 

 ently away from the nerve of sight to avoid all ill 

 effects. 



The turkey shares in all the above-noted peculiarities 

 of bird structure and bird habits, nest making, and 

 careful care of the young among the latter. Its nest, 

 however, is a very poor affair compared with that of the 

 majority of land birds, and consists but of a few dried 

 leaves or twigs on the ground, perhaps under the 

 shelter of some bushes or of a fallen tree. It is the 

 weaver birds birds of the Old World which construct 

 the most elaborate nests known. They construct immense 

 ones, or rather a huge cluster of nests placed sociably side 

 by side, under one cover, each nest having its own separate 

 entrance on the under side of the whole structure, and 

 not communicating with the nest next to it. The whole 

 mass may be ten feet in diameter, and ultimately break 

 down from its own weight. 



For details as to the habits of the turkey, readers 

 may be referred to American ornithologists, one of the 

 most distinguished of whom is Dr. Elliott Coues. But 

 Audubon long ago gave a graphic picture of the parental 

 care of the female turkey. It is the Old World, how- 

 ever, which affords us the most striking examples both 

 of parental and conjugal virtue and defect. There are 



