14 Maine; agricui^tural experiment station. 1910. 



the lateral side of the ovary and oviduct as far backward as the 

 caudal margin of the sac. This lateral attachment of the sac 

 is to the kidney, dorsal oviduct ligament, and body wall. 



The air sac thus forms a partition to the body cavity com- 

 plete as far caudad as it extends.* Ventral to the sac lie the 

 left lobe of the liver, the proventriculus, the spleen and the 

 gizzard, while; the cavity dorsal to the sac contains the ovary 

 and parts of the intestine and oviduct. In the normal condition 

 the sac contains little air and clings to the organs which lie 

 dorsal to it. The ovary occupies the anterior end of the cavity 

 dorsal to the sac. Since the attachment of the air sac passes 

 along the medial, cranial and lateral margins of the ovary, this 

 organ is walled off from the other viscera in all directions 

 except caudally by the anterior portion of this sac. 



The caudal relation of the ovary to the rest of the viscera 

 depends on its size. It changes as the ovary enlarges with 

 the approach of a laying period or egg cycle. In pullets and 

 hens not in laying condition the reproductive organs are small 

 and the other viscera occupy most of the abdominal cavity. A 

 part of the intestines crowd forward between the ovary and 

 the air sac. The viscera normally found in this position are 

 the transverse part of the small intestine and that portion of 

 the left coecum which lies parallel to it.f The mesentery of 

 this part of the intestine is reflected from the body wall just 

 caudal to the attachment of the ovary. Mesially it is fused 

 with the mesentery of the proventriculus and laterally it is con- 



* Butler (Proc. Zool. Soc. London, 1889, PP- 452-474, Plates XLVI- 

 XLIX) describes and figures on both sides in both sexes of the chick a 

 partition which he calls the oblique abdominal septum or the anterior 

 part of the post hepatic septum. He shows by a study of the embryology 

 that this septum develops in connection with the abdominal air sacs 

 which grow between and separate its two layers of peritoneum. In the 

 adult this septum is apparently represented by the peritoneum covering 

 the sacs. He does not discuss the relation of this partition to the vis- 

 cera but his figures show the gonads lying dorsal to it. On the left side 

 of the female they show the ovary shut off from the viscera by the sac. 

 In the present paper this partition of the left side of the female is de- 

 scribed as it appears in the adult, i. e., as the left abdominal air sac. 



fin two individuals this part of the intestine and coecum was found 

 to lie caudal to the ovary and dorsal to a loop of the small intestine 

 which projected forward ventral to the ovary. In neither of these cases 

 were there large yolks on the ovary. 



