358 Sir W. H. Flower on the General 



parent. A conical egg placed on the ground or a ledge of 

 rock is less liable to roll away from its place, if disturbed, 

 than one of a spherical form. 



Spheroidal eggs are illustrated by those of the Scops Owl, 

 Tawny Owl, Green Bee-eater, and Diving Petrel [Pelecanoides 

 urinatrix) ; the ordinary elliptical form by the Nightjar and 

 Sand-Grouse {Pterocles exustus) ; the long ellipse by the 

 Rough-faced Shag [Phalacrocorax carunculatus) ; the bi- 

 conical form, or pointed at both ends, by the Sclavonian 

 Grebe; true oval by the Wild Turkey, Dipper, and Common 

 Partridge — the last being transitional to the next form ; 

 conical or pyriform, exemplified by Hydrojjhasianus chirurgus, 

 the Dunlin, and Lapwing, the four eggs of which are arranged 

 with their pointed ends together, to show the way they lie 

 in the nest ; and, lastly, the elongated modification of the 

 conical by the Guillemot. 



Size. — The size of the egg has generally, but by no means 

 constantly, some relation to that of the parent bird. It also 

 depends very much upon the degree of development the 

 young bird attains at the time of hatching. In the case of 

 birds in which the young are hatched in a very immature and 

 helpless state, the eggs are small relatively to the size of the 

 parent. These birds usually build carefully-constructed 

 nests, suitable to contain the young brood during the first 

 period of their existence. When the young are well clothed 

 with down, and can run and fetd 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 the size of the egg 

 in some cases. Thus, the Cuckoo, which lays its eggs in the 

 nests of birds much smaller than itself, has eggs of a size 

 nearly corresponding to theirs, and therefore relatively the 

 smallest of any of the class. 



The statements upon this subject are illustrated by placing 

 side by side on one tablet the eggs of the Curlew and Raven, 

 the Guillemot and Raven, the Snipe and Blackbird, and, more 

 striking still, one of Mantell's Apteryx (of which a fine speci- 

 men has been presented for the purpose by the Hon. Walter 



I 



