ABSTRACTS. 349 



oviduct at autopsy and to discuss the formation of these ab- 

 normalities from the physiological point of view. 

 The chief results of this study were as follows : 

 i. A membrane-covered or hard-shelled normal or dwarf 

 egg may be returned up the duct and may either meet its suc- 

 cessor and return with it,, becoming enclosed in a common set 

 of egg envelopes, or not meeting its successor it may again be 

 forced through the duct stimulating the secretion of a set of egg 

 envelopes around itself. 



2. The number of egg envelopes common to the enclosed 

 egg and the yolk of the enclosing egg or the number of egg 

 envelopes which surround the enclosed egg when the enclosing 

 egg has no yolk depends apparently on the level of the duct at 

 which the enclosed egg resumes its normal direction toward 

 the cloaca. 



3. The enclosed egg is usually forced up the duct without 

 turning on its axis but occasionally the poles are reversed. 



4. A similar reversal of poles sometimes occurs in normal 

 laying and it seems probable that in both cases this turning 

 takes place in the uterus when the first powerful contractions 

 of the uterus bring the outwardly directed end of the egg 

 slightly above the opening from the shell gland into the vagina 

 and tangentially against the curved caudo-dorsal angle of the 

 uterus. 



5. The enclosed egg usually precedes its successor through 

 the duct and. therefore, usually lies in the pointed or anterior 

 end of the enclosing egg, while the yolk of the enclosing egg 

 lies in the blunt or posterior end. 



6. However, in two known cases where the enclosed egg 

 united with its successor after the latter had received practically 

 all its thick albumen there is evidence that the two eggs came 

 side by side in the duct with their long axis parallel and in one 

 case they certainly passed through the duct side by side with 

 their long axes parallel to each other and also parallel to the 

 long axis of the duct. 



7. There has been one case described with the yolk in the 

 pointed and the enclosed egg in the blunt end of the enclosing 

 egg. There is some doubt about the accuracy of this observa- 

 tion but it is possible that two eggs can pass in the duct. 



