io8 PHYSIOLOGY OF THE INVERTEBRATA. 



liver of Arion rii/us, as well as Helix, is a digestive gland 

 which is comparable to the pancreas of the Vertebrata. It 

 contains neither biliary pigments nor biliary acids. If one 

 considers that the Vertebrate liver is not a digestive gland in 

 the proper sense of the word, since neither bile nor an infusion 

 of hepatic tissues contains digestive ferments, we may conclude 

 that the name of liver is in no way applicable to the diges- 

 tive gland of the Gasteropoda. 



It is stated by Barfurth that the liver of the Gasteropoda 

 performs the functions of a hepato-pancreas. It is certainly 

 pancreatic in function; but there are no chemico-physio- 

 logical reasons for saying that it also possesses a hepatic 

 function. 



The salivary glands and "liver "of Patella vulgdta have 

 been investigated by the author.* The limpet (JP. vulgata), 

 with its conical shell adhering to the rocks of our coasts, is 

 well known to every sea-side wanderer. This member of the 

 Gasteropoda, has been the subject of many scientific memoirs 

 in ancient and modern times. Amongst naturalists, Aristotle 

 was the earliest who gave an account of some of the limpet's 

 habits, and Cuvier was the first to describe its anatomy. 

 Although this interesting little animal has attracted the 

 attention of many naturalists, it is only within the last 

 decade that the ti-ue functions of its internal organs have 

 been satisfactorily worked out. 



The " liver " of Patella vidgata is a yellowish saccular gland, 

 and the greater bulk of this organ is encircled by the super- 

 ficial coil of the intestine. Its secretion acts upon starch- 

 paste converting the starch into glucose, as proved by 

 Pehling's solution. The secretion, as well as the organ itself 

 produces an emulsion with oils and fats, yielding subsequently 

 glycerol and fatty acids. The soluble ferment secreted bjr 

 the columnar cells of the epithelium of the gland is readily 

 extracted by either the Wittich-Kistiakowsky or KravkofiE 



* Dr. Griffiths in Proreedinr/s of Soyal Society of London, vol. 42, p. 393 ; 

 vol. 44, p. 328. 



