62 



Case 230 — continued. 



Varieties of the Domestic Fowl, Pheasant Hybrids and several 

 Fighting Game Cocks of historical interest from having fought in this 

 district, are exhibited 



A specimen of Black Grouse {Tetrao tetrix) that has assumed male 

 plumage is also on view. This is a variation that is somewhat common 

 among Game Birds. 



Case 231 . 



Cabinet of Eggs of British Birds. 



In this Cabinet are specimens of the eggs of British Birds, arranged 

 in their respective clutches, including all the nesting species and most 

 of the birds that visit the British Islands. The birds that breed and 

 build nests in the neighbourhood are distinguished by a red asterisk. 



A key list of the birds is placed over the case, arranged alphabetically 

 with cross references, giving the number of the drawer opposite each 

 bird, in which its eggs may be found. 



Case 232. 



A case arranged to facilitate the comparative study of 

 Birds' Eggs. 



(a) Structure of egg shell and the surface grain or texture of eggs. — 



The egg shell is composed of carbonate of lime which is secreted 

 by the shell gland and spread over and around the egg shortly 

 before the egg is laid. (Hence the necessity for lime salts in the 

 food of birds generally). 



In certain families the egg shell exhibits a definite grain or 

 texture and in some cases species of the same genus are so distin- 

 guished. Examples of this latter condition, which may be called 

 specific differences are seen in the difference between the Trumpeter 

 Swan *(1) and Mute Swan (2), or between the Grey Lag Goose (3) 

 and Pink-footed Goose (4), examples of which are shown. 



According to appearance, eggs may be grouped under the 

 following heads : — Smooth, Glossy, Porcellanous, Greasy, Chalky 

 film, Dull and Granulated. 



Smooth Variety. The majority of birds lay eggs with a smooth 

 surface. Examples shown are Pheasant (5), Red Legged Partridge 

 (6), Moor Hen (7), Golden Plover (8), Oyster Catcher (9), Song 

 Thrush (10), Jay (11), Skylark (12), Butcher Bird (13), and Wheat- 

 ear (14). 



*The numbers here given are tbe numbers of the specimens in the Case. 



