486 



MANUAL OF ZOOLOGY 



SECT. 



top, built of grass, earth, and 

 (Diomedea melanophrys^ &c.), 

 burrow, as in many Petrels, 

 or it may be more or less 

 sticks, moss, leaves, hair, or 

 of constructive skill from the 

 the Pigeon and Eagle, to the 



sh./n 



manure, as in the Molly mawks 



It may take the form of a 



Kingfishers, and Sand-martins, 



elaborately built or woven of 



feathers, showing every stage 



rude contrivance of sticks of 



accurately constructed cup- or 



alb 



FIG. 276. Gallus bankiva (domestic Fowl). Semi-diagrammatic view of the egg 

 at the beginning of incubation, a. air-space ; alb. dense layer of albumen ; 

 alb', more fluid albumen ; bl. blastoderm ; ch. chalaza ; sh. shell ; sh. in. shell- 

 membrane ; sh.i, sA.s, its two layers separated to enclose air-cavity. (From 

 Marshall's Embryology, slightly altered.) 



dome-shaped nests of many familiar Passerine Birds. In 

 the Tailor-Bird (Orthotomus) it is formed of leaves sewn 

 together, the beak acting as needle : in a Malayan Swift 

 (Collocalid) it is largely built of the secretion of the Bird's 

 buccal glands. 



After the egg is laid, the process of development is arrested 



