8 



vacuole, and a denser homogeneous layer next the cross v/all 

 (fig. o) . Nuclei are quite abundant in the granular layer 

 "but are not of usual occurrence in the homogeneous portion 

 of the pad. Spherical bodies, probably of a proteid na- 

 ture, of various sizes, occur commonly in both layers of 

 the cytoplasm over the cross walls. 



In Griffiths ia barbata , BERTHOLD {*Q6) found the cyto- 

 plasm divided into a clear outer la.yer and a granular in- 

 ner layer, the latter containing the nuclei and the chro- 

 me-tophores. This seems to be the usual arrangement of the 

 protoplasmic elements in the coenocytes of algae. In Grif~ 

 fithsia Sornetiana. the cytoplasm becomes plainly differ- 

 entiated into two layers only v/here it reaches a consider- 

 able thickness, as in the thic]<:ened pads mentioned above 

 and in very young cells in which the sap-vacuole is still 

 small. 



Intercellular connections are conspicuous in living 

 as in stained specimens by reason of the peculiar plugs 

 which close the otherv/ise open pit betv/een the cells, 

 Griffithsia is an unusually favorable form in whic]i to 

 observe the interce]lul?:r connections because of tlieir 

 large size. Evidence presented below is believed to be 

 strongly in favor of the view, doubted by many workers, 



