No. i.] 



THE LESSER PERITONEAL CAVITY. 



173 



G.D. 



On the right side a marked gastric diverticulum is present, as 

 shown in Fig. 6. On the left side absolutely no diverticulum is 

 present. The same holds true 

 for all the sections pictured by 

 Professor His in his Atlas. Al- 

 though there are two gastric di- 

 verticula in the chick, I have found 

 in a specimen of sixty hours a 

 single right diverticulum, much 

 like the one shown in Fig. 6. 

 This may indicate that the left 

 diverticulum is in process of de- 

 generation. 



In a human embryo seven milli- 

 metres long the gastric divertic- 

 ulum is slightly larger than the 

 dog just described. It corre- 

 sponds about with His's A, B, 

 and Br 5 } The embryo was cut 

 into a perfect series, and I have reconstructed in wax the whole 

 embryo. A cast of the ccelom was made with Wood's metal. 



The pericardial cavity 

 surrounds the heart with 

 the exception of the 

 point where the sinus 

 reuniens enters. The 

 bulbus aortae is com- 

 pletely surrounded by a 

 space to its origin in 

 the ventricle. The cav- 

 ity communicates on 

 either side with the 

 pleuro-peritoneal. It 

 then surrounds the in- 

 testine, liver, and ex- 

 tends about the om- 

 On the ventral side of 



P.P. 



Fig. 6. Corrosion preparation of a 

 portion of the right coelom, including 

 the gastric diverticulum of the dog 6 

 millimetres long. Ventral view. En- 

 larged 66 times. G. D., gastric diver- 

 ticulum; P. P., pleuro-peritoneal cavity. 



P.P. 



D. 



Fig. 7. Corrosion preparation of the gastric di- 

 verticulum of a human embryo 7 millimetres long. 

 Enlarged 44 times. P.P., pleuro-peritoneal cavity; 

 F. IV., foramen of Winslow; G. D., gastric divertic- 

 ulum. 



phalo-mesenteric vessels into the cord. 



the alimentary canal, both on the oral and aboral sides of the 



1 Anatomie menschlich. Etnbryonen, and Ablandl. d. K. S. Ges. d. IViss., Bd. XIY, 



