^°'ui^^ 1 Shufkldt, E^gs of Reptiles and Birds Compared. 23I 



tlu' shell ol tlic cj^i;^ ill \;iiiiius paits ol (he canal, and the histology 

 of the walls ul the o\icl.ii(t and the pigmentary glands — should 

 throw a very considerable amount of light on the question. 



Sometimes the same species of bird will lay eggs that vary in 

 many particulars, as in form, size, colour, and markings. No bird 

 exemplifies this better than the Australian Black-backed Magpie 

 {Gymnorhina tibicen). A number of eggs of this bird are here 

 figured on Plate XLI. (figs. 42-47), and several of these are hke 

 the corresponding ones on the coloured plate illustrating the 

 beautiful article by Mr. A. F. Basset Hull, R.A.O.U., published 

 in The Emu* 



Fig. 42 of Plate XLI. of the present article has a ground colour 

 of a somewhat pale greenish-slate, while the lines, blotches, dashes, 

 and other markings all over it are of a bright rufous brown or 

 rusty red ; besides these, there are some spots and dabs of a dull 

 lilac. As all of these eggs are given natural size, and can therefore 

 be easily measured on the plate, I have omitted giving their sizes 

 and forms. Fig. 45 closely resembles fig. 42 in the matter of 

 ground colour and markings, but departs from it in form, it being 

 a typically ovate egg. Entirely different from these last two are 

 the eggs shown in figs. 43 and 44, these having a ground colour 

 of a rather light bluish-green, with the markings as shown of a 

 rather pale hair-brown. Except in form, these are like egg 

 No. 5 in Mr. Hull's plate, while 42 and 45 more closely resemble 

 his No. 3, though the markings in the former are more diffuse. 



Fig. 46 of Plate XLT. has a ground colour of a very pale 

 pinkish-cream, with the much-scattered little specks and spots quite 

 sharp, and in most instances with sharp, clean-cut edges. They are 

 of a rusty red as well as of a slaty hlac, being considerably massed 

 at the butt and widely scattered over the rest of the eg^. Mr. 

 Hull does not figure a specimen exactly like this one, though his 

 No. 6 approaches it in a way. It is, however, a much darker 

 egg and differently marked, the spots being much less numerous 

 and darker. 



Finally, Mr. Hull does not figure an egg of this Magpie at all 

 like the one here shown in fig. 47, which likewise has a pale 

 pinkish-cream ground colour, with the markings of a rusty-red 

 and slaty-violet. These consist of large and small isolated and 

 blurred spots, which tend to congregate at the butt, though only 

 upon one side of the egg. This specimen is likewise marked all 

 over with faint hair-line tracings of a bright rusty-red colour, 

 which are very evenly distributed, and greatly conduce to its 

 beauty. Now, in these eggs of the Australian Magpie we have 

 both hair-line markings and spots on the same specimens ; some 

 of these may be sharp and others blurred, while there may like- 

 wise be massing of the different markings at the butt on the same 

 egg. These may all be explained through what I have attempted 

 to set forth in previous paragraphs of this article, as any egg 



* Emu. vol. xiii., pp. 15, 16, Plate V. 



