Description of avian eggs’ shapes using geometrical standards

The original technique of description of avian eggs on the basis of the geometry of asymmetrical oval (ovoid) - a figure with parameters: D=1,0; L=2-(√(2/2); ri=0,5; rl =2,0;rc= 1-(√(2/2) - is described. Specific properties of this figure allow creating a system of 80 basic ovoid standards, each given an appropriate name, digital and letter coding, and distinct quantitative characteristics. Combining infundibular zones (blunt poles) of basic ovoids in pairs gives 80 standards of symmetric pseudo-ovoids, 44 of which are found in birds. The same procedure applied to different ovoids produces 375 standards of asymmetrical pseudo-ovoids. They can be divided into six groups. Use of such system of standards enables us to identify real shapes of avian eggs, to analyze relation of morphometric parameters to incubatory properties of eggs, and also to carry out comparisons and generalizations of other authors’ data. Each standard is quantitatively characterized by means of indexes of infundibular, cloacal and lateral zones, by the index of asymmetry, elongation index, complementarity index as well as interpolar index.