G4STR0MEPiTIC 

 LIGAMENT 

 UNG \ PLEURO 



Fig. 363 (A-1, 2, 3). Diagrams showing the invasion of the peritoneal coelom around 

 the liver and relations of septum transversum and diaphragm to the liver. (A-1) The 

 peritoneal invasion separates the liver substance away from the lateral body wall and 

 also from the anterior face of the liver itself. The separated, thickened, anterior face 

 of the liver (see fig. 362, I-l and 1-2) forms the primary septum transversum (peritoneo- 

 pericardial membrane). (A-2) The relation of the liver and other viscera to the 

 secondary septum transversum formed by the addition of the dorsal closing folds (see 

 fig. 362D) to the primary septum transversum. (A-3) This is a diagrammatic repre- 

 sentation of conditions shown in B. Observe position of various ligaments associated 

 with the liver. (B) Sagittal section through opossum embryo presenting relation of the 

 liver to diaphragm. The ventral part of the diaphragm is the remodeled primary septum 

 transversum. Observe that the inferior vena cava perforates the diaphragm. The area 

 of attachment of the liver to the diaphragm is the coronary ligament. (The preparation 

 from which this drawing was made was loaned to the author by Dr. J. A. McClain.) 

 (C) Pericardioperitoneal opening below the esophagus in the shark, Squalus acanthias. 

 (See also fig. 362D.) (D) Schematic diagram, dorsal view, of initial stage of devel- 

 oping pleural cavities in the mammal showing the anterior and posterior lateral body 

 folds. The anterior lateral body fold gives origin to the pulmonary ridge or rudiment 

 of the pleuropericardial membrane and the posterior lateral body fold forms most of 

 the pleuroperitoneal membrane. Cf. fig. 362E. (E-H) Schematic diagrams showjng later 

 stages in separation of pleural cavities in the mammal, viewed from the dorsal aspect. 

 Observe that the pleuroperitoneal membrane is formed from two rudiments, viz., the 

 posterior lateral body fold and a very small splanchnopleuric contribution (fig. 363F). 



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