STRUCTURE OF THE EARTHWORM. 159 



5. The greater part of the wall of the pharynx is made 

 up of a mass of muscular fibres, which are entwined in all 

 directions. 



5. In a section through the oesophagus (Fig. 88), notice 

 that, 



1. The muscular wall is divided into an outer layer (o) 

 of longitudinal fibres, and an inner layer (p) of circular 

 fibres. 



2. The epithelium (n) is thrown into folds or papillae, 

 and each contains a looped branch of a blood-vessel. 



3. The cuticle (m) is more distinct than in the sections 

 of the pharynx. 



c. In a section through the cesophageal glands notice that 

 these are simple pouches formed by pushing out the wall 

 of the ossophagus into the body cavity. The most ante- 

 rior pair contain the calcareous bodies noticed in Section 

 XV. 



d. Sections through the crop and gizzard are much like 

 those through the oesophagus, except that the muscular 

 layer is much more developed. 



e. In sections through the intestine (Fig. 89) notice the 

 very peculiar manner in which the dorsal wall (/*) is 

 pushed down towards the ventral, thus reducing the cav- 

 ity (i) to a narrow slit. Notice that the epithelium (j), 

 the vascular layer, the layer of circular muscular fibres (&), 

 and the layer of longitudinal muscular fibres (?) are ar- 

 ranged as in the oesophagus. 



1. Outside the layer of longitudinal fibres notice a 

 thick layer (m) of granular greenish cells, which is re- 

 flected above onto the dorsal vessel (<?) and its branches, 

 thus forming the so-called liver (o). 



