Vol. xxxvi.] 14 



For example : (1) While the usual shape of the egg is 

 oval, there are exceptions in some groups, such as the 

 " ovalaire " shape of the Tinamous, the "elliptique" shape 

 of the GrebeSj Cormorants, and Pelicans, the " ovoiconique ''' 

 with the Penguins and Guillemots, and the " cylindrique " 

 with the Megapodes and Sand-Grouse; or, to take examples 

 from the British list, the Accipitres, Meropes, and Halcyones 

 may be cited as orders in which the shape is spherical, 

 the Limicolae as oviconical, and the Caprimulgi as cylindrical. 



(2) That not a single aquatic bird has a glossy-shelled 

 e^^ : this character is confined in varying degrees to land- 

 birds. 



(3) Eggs of any given species do not vary according to 

 climate. 



(4) The type o£ coloration, though varying in different 

 species indefinitely!, is, nevertheless, constant in certain 

 families — e. g., white in the Pigeons, unicoloured and without 

 markings in the Pheasants and Tinamous. 



(5) The shape and style of markings, apart from colour, 

 are also characteristic of certain groups, such as the Buntings, 

 the Grackles, and most of the American Orioles (Icteridse). 



In the classification which follows great stress is laid on 

 the shape of the e.^^, while the texture of the shell and the 

 colour and markings are also taken into consideration. The 

 author then proceeds to take the various suborders, tribes, and 

 families separately, and shows how wonderfully, on the whole, 

 the oological characters follow the natural groups, though not 

 equally clearly in every case. Thus, in the first suborder, the 

 Accipitres, there are striking oological differences between the 

 Vulturidae, the Aquilidse (under which head are included such 

 forms as Haliaetus, Pandion, and Circaetus), and the Falconidse 

 (including, besides the true Falcons, the Goshawks (Asturinse), 

 and Harriers (Circinse), as well as the Secretary Birds 

 i^Gypogeranus)). On the other hand, all the birds of the 

 order Ptilopteri, comprising two tribes, the Aptenodytae and 

 the Eudyptidse, although varying in shape from spheroidal 

 to oviconic, agree in absence of colouring-matter. It is 

 unnecessary here to analyse his results in detail, especially 

 as in most cases he reserves his oological characters for 



