REPRODUCTION IN THE DOMESTIC FOWL. 183 



the sac was continued into a stalk about the size of the index 

 finger. The sac and appendage were covered with a very thin 

 layer of shell. The membrane was ruptured at the foot of 

 the stalk, exposing a large area of the shell of the normal egg 

 which was included. The torn edges of membrane were stuck 

 tight to the shell of the included egg apparently by the thin 

 layer of shell which covered the membrane. There were also 

 folds in the membrane at the foot of the stalk and the inner 

 parts of these folds were not covered with shell. Apparently this 

 rupture and folding of the membrane took place before the 

 shell on the enclosing egg was formed. It will be noted that 

 the enclosed egg lies entirely to one side with its pointed end 

 toward the pointed end of the enclosing egg. At the pointed 

 end of the enclosing egg there is a fresh rupture. From this 

 albumen and yolk were protruding when the egg was found. 

 The yolk had been broken but appeared to have been a normal 

 yolk. The stalk was still filled with albumen. Evidently 

 this rupture had occurred when the egg was laid and was no 

 doubt due to the large size of the egg. The enclosed egg was 

 normal in all respects. Apparently this normal egg had been 

 forced back up the oviduct without reversing its polarity. It 

 apparently met the succeeding egg at the posterior end of the 

 albumen secreting region since it evidently lay quite outside 

 the albumen of this egg. The shape of the enclosing egg indi- 

 cates that the two eggs passed through the isthmus side by 

 side. There was no membrane around the enclosed egg. That 

 is it did not receive a membrane when it passed up the duct. 



Specimen 2 (Plate II. and Figs. I and 2) was presented to the 

 Station by Mrs. Ethel Pike, of Winthrop, Maine. Several 

 days elapsed after the egg was laid before it reached the Station 

 laboratory. The egg was well protected but some evaporation 

 had evidently occurred as there were folds in the enclosing mem- 

 brane which was without shell. Within this membrane lay two 

 normal eggs with their long axes parallel. One of these was a 

 normal egg enclosed in an egg membrane and shell. The other 

 was a normal yolk enclosed in a normal albumen envelope. 

 There was a shallow layer of thin albumen common to the two 

 eggs. It will be seen in the photograph that the folds in the 



