PHYSIOLOGY OF THE INVERTEBRATA. 113 



utmost care) with dilute sulphuric acid, and to the distillate 

 ferric chloride solution was added, which gave a red colour, 

 indicating the presence of sulphocyanates. 



The inorganic constituents, as far as the author could 

 make out, consisted only of calcium phosphate. No calciuui 

 carbonate could be detected. 



There is much in favour of the supposition that the 

 diastatic ferment in these secretions is produced as the result 

 of the action of nerve-fibres (from the inferior buccal gan- 

 glion) upon the protoplasm of the epithelial cells of the 



glands. 



The Tunicata. 



The very fine, branched, and ampullated tubules (sometimes 

 known as Savigny's tubules), ramifying over the wall of the 

 intestine in nearly all the Tunicata, form a digestive gland, 

 which is certainly pancreatic in function. The common duct 

 of this gland opens into the stomach. The latter organ 

 always contains a secretion having similar chemical properties 

 to those produced by the pancreatic tubules. 



The two following tables summarise our studies of the 

 salivary glands and the so-called livers of the Inverte- 

 brata : — 



