388 PROCEEDINGS OF THE CANADIAN INSTITUTE. 
In the immediate neighbourhood of the epipharyngeal bones, the 
membrane becomes much thickened and thrown into folds, for the 
most part longitudinal. The thickness of the membrane here is due 
to the accumulation of striated muscular fibres, which at the com- 
mencement of the cesophagus forms a species of sphincter muscle. 
The passage of the pharynx into the csophagus is of a funnel 
form, its base being some distance posterior to the epipharyngeal 
teeth-pads. The folds give an appearance of ribbing to the funnel. 
this being seen most distinctly when the jaws are widely separated, 
The superior teeth-pads, one on each side of the middle line, are 
of round or oval shape, and situated on the epipharyngeal bones. 
The membrane surrounding and covering the pads is thin, sensitive, 
and contractile. 
The hypopharyngeal pads are rhomboidal on surface view and are 
placed opposite the epipharyngeals, with their long axis directed out- 
ward and backward. 
Both sets of structures are extremely sensitive. When the 
epipharyngeal pads are touched, the membrane shrinks, the pads are 
thrust down, and at the same time those of the floor are elevated in 
opposition. This is for the purpose of comminuting the food as it 
passes into the cesophagus, mere contact of food or other matter 
serving to bring the pads into action. 
The lining membrane of the straight cesophagus is longitudinally 
folded, and is perfectly colorless in the fresh condition. Its muscular 
walls are thick. Near its posterior end the cesophagus receives the 
opening of the duct of the air-bladder. 
The folds which anteriorly are longitudinal, become arranged in 
the stomach in every direction and disappear when it has been dis- 
tended by, and hardened in, chromic acid and alcohol. The openings 
of its glands are scarcely observable with the naked eye. 
The stomach of Amiurus belongs to the cecal type, the ccecum, 
however, not being distinctly marked off as such. It possesses with 
the cardia the same axis longitudinally placed, and is short blunt- 
cone like. Its ruye@ are like those of the cardia, and both portions 
are tinged chocolate-red when the stomach is in the digesting state. 
The pylorus, which is of smaller diameter, starts from the left side 
of the junction of the cardia and ccecum and extends forward beside 
the former to near its anterior termination, where a circular con- 
striction visible on the outer surface of the pylorus denotes its. 
