294 MAINE AGRICULTURAL EXPERIMENT STATION. I916. 



are normal in all other particulars. The thickness of shell 

 varies from very thin to very thick as in normal eggs. 



III. The Size and Shape Relations of the Several 

 Classes of Dwarf Eggs Compared to each Other and to 

 Normal Eggs and the Relative Variability of Normal 

 and of the Different Classes of Dwarf Eggs. 



There is a considerable amount of variation within each 

 class of dwarf eggs in respect to every measurable character. 

 For each class of prolate spheroidal dwarf eggs the mean, 

 standard deviation and coefficient of variation for each dimen- 

 sion and for weight was determined by the use of frequency 

 distributions. In the same way the means and standard devia- 

 tions were determined for shape index. Since this is a per- 

 centage character the coefficient of variation has no physical 

 significance. However, the relative variation of the shape in 

 the several groups may be roughly estimated by comparing 

 directly the standard deviations. The number of cylindrical 

 eggs was so small that the variation constants were not deter- 

 mined. The arithmetic means, however, were determined 

 directly from the data. The size and variation of the different 

 egg parts in dwarf eggs is an interesting but difficult question. 

 It was found possible to separate accurately the parts in a 

 dwarf egg with a small yolk enclosed in a yolk membrane. The 

 weights of the parts were determined for sixteen small yolked 

 dwarf eggs. The number is so small that the means, standard 

 deviations and coefficients of variation were determined directly 

 from the data. 



The means, standard deviations and coefficients of variation 

 for each character in each class of dwarf eggs and in two 

 groups of normal eggs previously studied 5 are given in table 2. 



""'Pearl, R. and Surface, F. M. 1914. A Biometrical Study of Egg 

 Production in the Domestic Fowl. III. Variation and Correlation in 

 the Physical Character of the Egg. U. S. Dept. Agr. Bur. Anim. Indus. 

 Bui. no, Pt. Ill, pp. 171-241. 



Curtis, M. R. 1914, b. A Biometrical Study of Egg Production in the 

 Domestic Fowl. IV. Factors Influencing the Size, Shape and Physical 

 Constitution of Eggs. Archiv f. Entw. Mech., Bd. 39, pp. 217-327. 



