SECTION THROUGH PHARYNX 



189 



3. The atrial cavity has the same general relations as in 

 B. The atrial epithelium covers the outer surfaces 

 of the branchial bars, and the suspensory folds of 

 the pharynx; and is continued downwards along 

 the inner surfaces of the atrial folds, covering the 

 reproductive organs, and being thrown into folds 



FIG. 33. Amphioxns lanceolatns. Transverse section through the 

 hinder part of the pharynx of an adult female, passing through the 

 liver and ovaries. The boundary of the atrial cavity is indicated 

 by a thick black line. (A. M. M.) 



A, skeleton of dorsal fin. B, spinal cord. C, notochord. D, connective- 

 tissue sheath of notochord. E, cavity of pharynx. F, hyperbranchial 

 groove. G, hypobrH.nch.ial groove. H, atrial cavity. L, liver. M, dorsal 

 coalomic canal. U, branchial coalomic canal. O, coelomic space surrounding 

 liver. OV, ovary. P, metapleural coelomic canal. R, left dorsal aorta. 

 S, cardiac aorta. T, hepatic veins. 



