980 Journal of Agricultural Research voi.v1.No.2s 



From the last line of Table I it is seen that 96, or 35.03 per cent, of the 

 eggs opened were yolkless. The other 178, or 64.96 per cent, contained 

 yolk. Of these, 151, or 55.11 per cent, of all the dwarf eggs opened 

 contained yolk not inclosed in a yolk membrane. A small yolk was 

 present in 27, or 9.85 per cent, of the dwarf eggs. From these figures 

 it is seen that nearly two-thirds of the dwarf eggs contain yolk. 



II.— THE ALBUMEN AND SHELL OF DWARF EGGS 



We have seen that dwarf eggs differ in respect to the nucleus around 

 which the albumen is formed. Bonnet (3) states that the nature of the 

 albumen is also generally altered. The dwarf eggs observed differed 

 greatly in respect to the density of the albumen. In many it was 

 very condensed, being a thick clear mass which nearly maintained its 

 shape when removed from the shell and egg membranes. It appeared 

 very much like the albumen in a normal egg while it is in the albumen- 

 secreting region, or the isthmus of the oviduct (15). In many other 

 cases it appeared exactly like the albumen of a normal laid egg — that 

 is, there was a somewhat firm inner mass surrounded by a thin fluid 

 albumen. All gradations between these also occurred. In a very few 

 cases the albumen was more fluid than in the average normal egg. There 

 was, however, an undoubted general tendency for the albumen to be 

 more than normally firm. The density of the albumen was not deter- 

 mined accurately as a routine procedure in the dwarf eggs. Its apparent 

 density as compared to normal eggs was frequently, but unfortunately 

 not uniformly, recorded. In connection with another investigation in 

 progress at this laboratory the specific gravity and refractive index of 

 the albumen of many normal and a few dwarf eggs was determined. 

 These probably were not a random sample of dwarf eggs. The minimum 

 specific gravity of the sample of 7 dwarf eggs was 1.02824, while the 

 mean specific gravity for the sample of 180 normal eggs was 1.0288. 

 The dwarf eggs ranged widely, with the upper end of the range decidedly 

 above that for normal eggs. The maximum for dwarf eggs was 1.2 107, 

 against a maximum of 1.0415 for the normal eggs. The mean for the 

 dwarf eggs was 1.0627, which is higher than the maximum for normal 

 eggs. The range, however, overlaps, 4 of the 7 dwarf eggs falling within 

 the upper end of the range for normal eggs. In a sample of 10 dwarf 

 eggs the refractive index lay within the range for the sample of 180 

 normal eggs. The mean was slightly higher for the dwarf than for the 

 normal eggs; but this difference certainly was not significant. 



The egg membranes of dwarf eggs, so far as superficial appearances 

 indicate, are comparable to those of normal eggs. The shell is sometimes 

 entirely or almost entirely absent, as in the case of membrane-covered 

 or soft-shelled eggs, which are normal in all other particulars. The 

 thickness of shell varies from very thin to very thick, as in normal eggs. 



In the present investigation no further distinction is made between 

 dwarf eggs in respect to variation in albumen or shell. 



