328 MAINE AGRICULTURAL EXPERIMENT STATION. I916. 



21. The popular notion that a dwarf egg marks the end of 

 a period of production is without foundation. A dwarf egg 

 is equally likely to occur at any time during a clutch or litter. 



22. A dwarf egg may be overtaken by a normal egg and 

 form one of the components of a compound egg similar to a 

 double-yolked egg except that one part is a dwarf egg. 



23. A dwarf egg after it has received its membrane or its 

 membrane and shell, may be returned up the duct and be 

 included in the succeeding normal egg, or it may act as the 

 stimulus for the formation of a larger enclosing dwarf egg. 



24. Dwarf eggs are produced only when the ovary is in the 

 absolutely active condition associated with the maturing of 

 yolks. This is true whether the bird has a normal or a patho- 

 logical oviduct. 



25. When the sex organs are in this condition a mechanical 

 stimulation of the oviduct by an artificial yolk may result in 

 the formation of a complete set of egg envelopes. 



26. The mechanical stimulation need not begin at the funnel 

 in order to be effective to the parts lower down. 



27. The mechanical stimulation is local in its effect. That 

 is, it is not transmitted down the duct any distance below the 

 point to which it is applied. 



28. Dwarf eggs may be, and probably often are, produced by 

 the stimulation of an active duct by some material particle 

 which is not yolk. At least 65 per cent, of the dwarf eggs 

 studied, however, were initiated by an abnormal small yolk or 

 by a part of a normal yolk. Certainly in some and probably 

 in all the latter cases the rest of the yolk was absorbed by the 

 visceral peritoneum. 



