REPRODUCTION IN THE DOMESTIC FOWL. 189 



in Fig. 4. It contained a normal hard-shelled egg surrounded 

 by a thin layei of albumen 1 which extended into the stalk. The 

 pointed end of the included egg lay toward the stalked end of 

 the including egg. The including egg did not show a per- 

 ceptible pointing of the end opposite the stalk but seveial 

 distinctly pointed stalked eggs have been observed at this labor- 

 atory. In all cases the stalk occurred at the blunt or air cell 

 end of the egg. Two stalked and pointed double eggs have 

 occurred (see Plate I. and Text-fig. 5) and in these cases also 

 the stalk was at the blunt end. Further eggs have been found 

 in the oviduct which had not rounded off completely at the end 

 toward the funnel but were trailing a stalk of albumen. In no 

 case has an egg been observed in the duct which was not rounded 

 off at the end which was toward the caudal end of the duct. A 

 few words in regard to the processes involved in shaping the egg 

 seem necessary at this point. 



Before the egg receives its egg membrane it is a fluid body 

 which tends to take a spherical form. It becomes elongated 

 in the direction of the long axis of the oviduct due to the fact 

 that the diameter of the oviduct is smaller than the diameter 

 of the egg if it maintained a spherical form. The outline of 

 an egg is sometimes nearly elliptical indicating that the duct 

 did not offer much resistance to the egg when the peristaltic 

 action of the duct walls forced it forward. More often, how- 

 ever, one end of the egg is distinctly more pointed than the 

 other. This distinction between the two ends is seen in many 

 of the membrane-covered eggs found in the isthmus at autopsy. 

 It seems probable that the relative tension of the longitudinal 

 and circular fibers of the duct wall at the time the egg receives 

 its membrane is the most important factor in determining the 

 shape of the egg. If the longitudinal fibers in the wall of the 

 duct ahead of the egg do not contract enough considerably to 

 enlarge the duct as the contraction of the circular fibers behind 

 forces it forward, the egg will meet with considerable resistance 

 and will tend to become pointed. In all cases observed where 

 an egg in the isthmus had its poles differentiated the pointed 



1 As the egg had been preserved in 70 per cent, alcohol, the albumen was coagu- 

 lated and its normal consistency could not be observed. 



