170 



MALL. 



[Vol. V. 



of the right diverticulum now lies on the left side of the body ; 

 the same position is held by the proventriculus and gizzard. 1 



L. 



P.P. 



Fig. 4. Corrosion preparation of the right gastric diverticulum in a chick of 136 

 hours. Ventral view. Enlarged 22 times. P. P., pleuro-peritoneal cavity; F. IV., 

 foramen of Winslow; L, position of right lung; P., position of proventriculus; O., 

 omental cavity : position of gizzard. 



On the left side the gastric diverticulum has become but 

 slightly larger than in the previous stage (Fig. 5). It commu- 

 nicates on its aboral side 

 most freely with the pleuro- 

 peritoneal cavity, and no in- 

 dication of a constriction 

 (foramen of Winslow) is at 

 any time present. 



A day later (six days, six- 

 teen hours) the left divertic- 

 ulum has nearly disappeared, 

 while the dimensions of the 



Fig. 5. Corrosion preparation of the left right haye i ncrease d COn- 



diverticulum in a chick of 136 hours. Ventral ..... . T 



view. Enlarged 22 times. P. P., pleuro- Slderably in Size. In gen- 

 peritoneal cavity; L. G., left gastric diverti- eral, its form is much as 



cuium; l, position of left lung. shown in Fig. 4. The lobus 



1 Duval, PI. XXIV, Figs. 527 to 535, represents sections of this stage. The sec- 

 tions are all viewed from the aboral side ; that is, they are negative pictures. 



P. 



