204 HENRY LESLIE OSBORN 



The posterior chamber is a globular dense body as seen in a whole- 

 mounted worm. The wall is thick and heavy, due not to the 

 presence of a heavy muscular coat as it would be if the organ were 

 a pharynx, but to the very peculiar structure of the cuticular coat. 

 The cuticle here, which is continuous with the thin layer of the 

 anterior chamber, suddenly changes its character and becomes a 

 mass of tall slender processes springing vertically from the wall 

 and projecting freely into the lumen of the organ. Their appear- 

 ance is shown in fig. 12. They bear some resemblance to the tall 

 processes of the epithelium of the intestine just above them, with 

 which they are directly continuous. They have every appear- 

 ance of having arisen from a cuticularized epithelium. In Coty- 

 laspis (Osborn, '04) there are similar indications of an epithelial 

 origin of the cuticle which lines the oesophagus. 



The posterior chamber of the oesophagus has almost no muscu- 

 lar tissue in its wall. A very few circular and longitudinal fibers 

 can be recognized, evidently strictly comparable with the muscles 

 of the intestine. There is however a coating on the inner surface 

 of the organ which is a condensation of the parenchyma at large. 

 This has a fine but definite boundary next the parenchyma. 



Oesophageal glands. Numerous cells lie in close proximity to 

 the oesophagus {oegl in fig. 12) which are not ordinary parenchyma 

 cells. Their massing too goes to show that they constitute a 

 definite organ whose position requires us to regard it in its work 

 as in some way a part of the oesophagus. The cells are not angu- 

 lar like those of the parenchyma but have rounded outlines. Each 

 cell has a nucleus poor in chromatin and a distinct nucleolus. 

 The sharp line in the figure passing on the left side of this group 

 of cells marks the boundary of the denser parenchyma which 

 ensheathes the oesophagus. It will be seen that the cells are 

 located outside of this sheath and so are somewhat remote from the 

 lumen of the oesophagus. An organ of this sort is usual in trenia- 

 todes; it is often called a 'salivary gland.' One writer however, 

 (Otto, '96) questions the salivary function of the cells in the Am- 

 phistomes, since he does not find any connection between them and 

 the lumen of the oesophagus. We shall however go on calling 

 these organs 'oesophageal glands' though we have no definite 



