Families PHASIANIDAE, PERDICIDAE 

 and TETRAONIDAE. 



(Plates 113-116). 



Of the Pcrdicidae, breeding in the Netherlands, P. perdix stands 

 through internal and external oological distinguishing features side 

 by side with Ph. colcfiicus. 



C. coturnix, although having its fundamental layer — tinged a pale 

 bluish green by oocyanin — in common with colchicus and perdix, 

 approaches through external oological properties closer to T. tetrix. 

 A special characteristic, peculiar to the coturnix-egg as well as to 

 that of tetrix, consists in the circumstance that in both eggs the 

 surface pigment layer and the spots are completely mingled, as it 

 were, with glutinous substance, and are only attached extremely 

 loosely to the shell. 



My examination further showed to me: 



1. that in the co/«r/!/x-eggshell, between the surface layer of 

 pigment mixed with gluten and the fundamental oocyanin layer, 

 there is an unspotted layer, coloured yellowish or greyish brown 

 which fully corresponds with the surface pigment layer of the 

 perdix-eggiypes. 



2. that in the /e/nx-eggshell all the lime layers under the sur- 

 face pigment layer are pure white (contain no oocyanin) down to 



