300 



A conical egg placed on the groiiiul or ledge of rock 

 is less liable to roll away from its place if disturbed than 

 one of a spherical form, a fact made use of in making 

 mechanical toys. 



Cards illustrating form are : 



(«/. Spheroidal : Scops' Owl, Tawny Owl, Green Bee-eater, 

 Diving Petrel. 



(b). Elliptical : Nightjar, I^esser Pintailed Sand Grouse,. 

 Chatliam Island .Shag (most perfect). 



(c). Biconical Sclavonian Grebe. 



(rf). True Oval : Wild Turkey, Dipper, and Grey Parrot. 



{e). Pyriform : Duidin Pheasant, Tailed Jacana (perfect). 

 A group of four I/apwing as in nest. 



4. — Sizp: : 



Size of egg has generally some relation to that of 

 parent bird. It also depends very much upon the degree 

 of development the 3'oung birds attain at time of 

 hatching. 



In the case of birds in which the young are hatched in 

 a very itnniature and helpless state the eggs are relatively 

 small to size of parent. These birds usually build carefully 

 constructed nests to contain young brood during first period 

 of their existence. 



When young are well clothed in down and can run 

 and feed themselves as soon as hatched, the eggs are large. 



Such birds usually lay on the ground in imperfectly 

 formed nests. 



Other circumstances seem to influence size of egg in 

 some cases. Thus Cuckoo, which lays in other bird's nests 

 much smaller than itself has eggs of a size nearly corres- 

 ponding to theirs and therefore relatively the smallest o 

 any of the class. 



Cards illustrating above. 

 {a). Birds of about equal size with different sized eggs. 

 Curlew and Raven, former large, latter small. 

 Guillemot and Raven ,, ,, 



Snipe and Blackbird ,, ,, 



Mantell's Apteryxand Crowned Pigeon ,, 



