S02 



ducts , which is distinctly to be seen, is a continuation of the 

 luembrane of the cell; there is no sbarp limit between thetn. 



I did not succeed in staiuing the nuclei, when 1 put the cells 

 alive in methylen blue, dissolved in 0,6 procent Na Cl solution; 

 other colouring processes failed likewise. The reason is, that the 

 numerous little grauules in the cell swelling and being stained , it 

 becomes impossible to distinguish them from the nuclei. By treating 

 the cells with diluted acetic acid the nucleus is distinctly seen 

 and the protoplasm remaius as a fine network. The cells have 

 but one nucleus, which is oval and shows a couple of nucleoli. 



In my sections, which are coloured with haematoxyline the 

 nuclei have a dark sharp outline. In contradiction to what Bourne 

 says I have observed uo difference between the prostomial glands 

 and the salivary glands; Bourne bas found that the granules of 

 the salivary glands were stained dark red with boraxcarmine , 

 whilst the prostomialglands were not coloured at all. I have re- 

 peated the experiment but with quite a different eff'ect. The gra- 

 nules of these glands as well as of the salivary glands and even 

 of the epidermicglands were all coloured dark red with borax- 

 carmine. 



The only diö"erence is that the prostomial glands are much 

 smaller than the salivary glands. 



On the other hand a very clear distinction is to be seen be- 

 tween the salivary glands and those of the skin. 



The latter are sometimes situated deeply among the muscular 

 fibres, in this case having a long secretory duet; these cells 

 have no granules at all and are only faintly stained by haema- 

 toxyline ; bigger granules occur when the glands keep nearer to 

 the surface. 



Leuckart was, in his former communication, of the same opi- 

 nion as Bourne and said : »Histiologisch sind übrigens diese ein- 

 zellige Drüsen (Lippendrüsen) — und Gleiches gilt von den opti- 

 schen wie chemischen Eigenschaften ihres Secretes — von den 

 Speicheldrüsen verschieden, dafür aber den in der Tiefe des Kör- 

 pers sehr allgemein (besonders bei den Kieferegeln) vorhandenen 



