ALIMENTARY CANAL, ETC., OF AMIURUS CATUS. 395 



ous with that bounding the remainder of the cell ; this was clear 

 enough evidence of the possession of a cell-membrane. Again, seve- 

 ral other forms or variations of structure were observed in a few 

 cases, and these I am in doubt whether to classify as normal or patho- 

 logical. They were obtained by maceration in Midler's fluid, and in 

 them the finely granular material of the neck and cap of the cell was 

 aggregated into clumps, with clear spaces between them ; in the cen- 

 tre of each of these clumps a round body, much smaller than the 

 nuclear body proper, was observed. The nuclear bodies themselves 

 retained their usual appearance. Sometimes an optical section of the 

 cell instead of showing clumps yet revealed their round central bodies 

 as regularly disposed as those of the clumps. 



Whether these structures are secretory or nervous in function it is 

 impossible to say. From the constant presence of the clear glassy 

 fluid, and its disposition at the head of the cell, one would be in- 

 clined to the former view. 



As already mentioned, the description of the mucous membrane of 

 the mouth applies equally to that of the pharynx. The slime cells, 

 however, increase in number, and just behind the teeth -pads they 

 become aggregated together into patches, one above and one below. 

 At the commencement of the oesophagus they dwindle away, and 

 before the posterior moiety of the oesophagus is reached have com- 

 pletely vanished. 



The clavate cells are distributed equally throughout mouth and 

 pharynx. 



A tran verse set of striated muscle fibres connect the two hypo- 

 pharyngeal bones. Behind them it gradually surrounds the pharynx, 

 and immediately before the oesophagus is reached it forms a thick 

 muscular layer. At this point is the origin of the muscle fibres 

 forming the inner longitudinal layer of the oesophagus. 



OESOPHAGUS. 



The low epithelium of the pharynx passes into that of the oesopha- 

 gus, with a gradual increase in the height of the constituent cells. 



The muscularis mucosce is represented by but a few fibres, while 



the submucosa is thin and shows no distinction from the tissue 



sheathing the longitudinal muscle bundles. These latter are widely 



separated and coarsely grouped, and, although first appearing an- 



28 



