232 



STUDY OF PIG EMBRYOS. 



internal structure. The body proper is divided by the diaphragm, Dia, into an 

 upper smaller pericardial chamber and a lower larger abdominal chamber. The 

 diaphragm is a thin membrane, which extends from the level of the base of the 

 fore leg, F.L, to the ventral wall of the body. The body seems filled chiefly by 

 three large organs: the heart, Au, Ven, above the diaphragm; and the liver, Li, 



Yen 



Dia 



Urn' 

 Yk.s 



CCBC 



COB 



Col 



II 



C:s 



Au 



- F.L 



Li 1 



Li 



W.B 



AU 



Clo 



H.L 



Soni 



FIG. 170. PIG OF 12.7 MM. DISSECTION OF THE VISCERA BY RICHARD E. SCAMMOX. 



AU, Allantois. Au, Auricle of the heart. Ccec, Caecum. Clo, Cloaca. Coe, Ccelom. Col, Large intestine. 

 C.s, Cervical sinus, nearly obliterated. Dia, Diaphragm. F. L, Front limb. H. L, Hind limb. //, Small 

 intestine. Li, Ventral, Li 1 , dorsal lobe of liver. Som, Cut surface of somatopleure. Um, Wall of the um- 

 bilical cord. Ven, Ventricle bf the heart. W.B, Wolffian body. Yk.s, Yolk-stalk. X 8 diams. 



Li 1 , and Wolffian body, W.B, below the diaphragm. The heart shows its large au- 

 ricle, Au, the walls of which are thin and translucent. It entirely conceals the veins, 

 which enter the heart through the diaphragm, and the aorta, which runs from the 

 ventricle toward the pharynx. The ventricle, Ven, is much larger than the auricle; 

 its walls are not translucent; its rounded apex points away from the auricle. The 

 liver lies close against the diaphragm and shows two lobes: the larger ventral lobe, 



