BY R. VON LENDENFELD, PH.D. 681 



Seen from the surface these problematic ganglia cells generally 

 appear circular (fig 4), but sometimes, although rarely, processes 

 are found (fig. 3), apparently radiating from them. These would 

 support the hypothesis put forth by Jickeli, that the structures in 

 question are ganglia cells. 



Should we however, assume these structui"es to be only nuclei, 

 then we must consider the veiy minute bodies in them as nucleoli. 



This species has been discovered in a pool at Moore Park where 

 it grows in abundance, by Mr. Whitelegge, who has kindly preserved 

 specimens for me for description. 



EXPLANATION OF PLATE XL VIII. 



Fig. l.~ Hydra hexactinella. R. v. L. 



3:1 magnified. 

 Fig. 2, -Optical longitudinal section tlirough portion of a tentacle of 

 Hydra hexactinella, osmic acid, Beale's carmine. 



magnified 250:1. 



(g) ganglia (?) cell. 

 Fig. 3 and 4.— Ganglia (?) cells seen from the surface. Osmic acid, Beale's 

 carmine 



magnified 400:1. 

 Fig. 3.— With two nervous (?) processes. 

 Fig. 4. — The usual kind without processes. 



