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stomach and caecum and the contraction of those around the oesophagus and 

 intestine. 4) The stomach may open into the intestine. The relaxation of the 

 sphincters around the gastric and intestinal openings and the contraction of those 

 around the oesophageal and caecal openings may produce this connection. 5) The 

 caecum opens into the intestine. 6) The hepatic duct opens directly into the 

 caecum. 7) The shape and position of the hepatic valve suggest two possibilities : 

 first, that the valve may close over the hepatic duct and prevent the regurgi- 

 tation of fluids from the caecum ; second , that the valve may be apposed to the 

 caecal wall so as to form a canal which leads, even when the opening from the 

 caecum to the intestine is closed, from the hepatic duct to the intestine so that 

 the digestive fluids which ordinarily pass directly from the hepatic duct to the 

 caecum may be diverted to the intestine and through it to the stomach. This 

 second possibflity is strongly suggested by the form and position of the valve 

 but there is great doubt whether this ever occurs. The explanation of this 

 remarkable connection between the portions of the gut is to be found in the 

 great difference in structure and in function between the stomach and caecum. 

 The stomach , oesophagus, and mouth (that is the entire gut as far as the opening 

 from the stomach to the caecum) are lined with chitin and, with the exception 

 of the glandular epithelium upon the unexposed surfaces of the tongue and palatine 

 lobes, is nongiandular. The three salivary glands are connected with the mouth 

 but they are so small that they can scarcely have a predominant digestive function 

 and, unless they do produce a remarkably effective digestive fluid, the tood in the 

 stomach is not digested by fluids produced by the anterior portion of the alimen- 

 tary canal. Nevertheless, the examination of the contents of the stomach of a 

 large number of squid shows that digestion does take place in the stomach for 

 the ingested food is found in the stomach in all stages of digestion from 

 large angular pieces wholly undigested to a mass of bones and bits of chitin 

 from which aU flesh has been removed. The caecum and intestine, on the other 

 hand , are lined by a ciliated secretory epithelium and receive the secretion from 

 the immense digestive glands, the liver and pancreas. The structure of the 

 stomach and caecum naturally leads to the supposition that the stomach is 

 merely a crop for storing food until it can be passed into the caecum for diges- 

 tion but in the large number of individuals examined, bones, chitin, or pieces 

 of undigested food were never found in the caecum while , as has been stated , 

 partially digested food and indigestible substances are found in the stomach. 

 Hence it seems clear that the first stages of digestion , at least , occur in the 

 stomach. All these facts lead us to the foflowing conclusion which agrees with 

 that of BouRQUELOT who reached the' result from a study of the physiology of 



