192 MAYNIE R. CURTIS. 



and the egg reverses ends. In the region of the uterus the 

 ventral ligament becomes a thick band of muscle fibers from 

 which fibers extend over the uterus, some of them reaching the 

 caudo-dorsal angle of the body wall. This band of muscles is 

 no doubt an important, perhaps the chief mechanism concerned 

 in extruding the egg. Since it is heaviest on the ventral side of 

 the uterus and since fibers connect it to the body wall dorsal 

 to the opening of the vagina, it seems reasonable that their 

 contraction in normal laying may sometimes bring the point of 

 the egg against the uterine wall dorsal to the opening of the 

 vagina and that in such a case the egg reverses ends. 



In cases 6 and 7 the reversal of the axes of the included egg 

 may have occurred in this manner and then a change in direction 

 of the muscular action of the duct may have forced the egg back 

 up the duct pointed end first. In the albumen-secreting region 

 the direction was again reversed. In each of these cases the 

 included egg appeared to be the only nucleus of the including 

 egg and it seems probable that it furnished the necessary stimulus 

 to cause the secretion of the including egg envelopes. There 

 was no membrane immediately surrounding the included egg. 

 Evidently it did not acquire one going up. 



Specimens 8 and 9 were found in oviducts during routine au- 

 topsy work. They show the processes of double egg formation 

 in actual operation. Specimen 8 was found in the albumen- 

 secreting region with its posterior end 16 centimeters from the 

 beginning of the isthmus. The included egg was surrounded by 

 a layer about one half cm. deep of very thick albumen. Under- 

 neath this was a firm egg membrane within which was a normal 

 hard-shelled egg surrounded by a layer of thick and one of thin 

 albumen. Evidently this egg had been forced from the uterus 

 up the duct to the albumen-secreting region. Since there was 

 no membrane around the egg inside the albumen envelopes it 

 could not have received a membrane going up. In the albumen- 

 secreting region its direction was again reversed and it evidently 

 stimulated the secretion of albumen and egg membrane. It was 

 then again returned into the albumen-secreting region where it 

 again stimulated the secretion of albumen. In this condition 

 it was found at autopsy. 



