Spencer. — On the Fresh-water Algse of New Zealand. 293 



fertilization seen in some normally wind- or insect-fertilized flowers at 

 certain seasons. In fact, we find cleistogamous flowers in our subaqueous 

 plants as well as in their aerial congeners. 



(Edogoniace^. 

 CEdogonium ciliatum (?), H., Hi. 

 ,, compressum, H., liii. 



OSCILLATOEIACE^ . 



1. Bacterium, M, Die, p. 3. 



2. Vibrio rugula (?), M. Die, p. 3. 



3. Spirillum volutans, M. Die, p. 3. 



4. Spirulina jenneri, M. Die, p. 3. 



5. Oscillatoria autumnalis, H., Ixxii. 

 decorticans, H., Ixsi. 

 nigra, H., Ixxi. 

 tenuis, H., Ixxii. 

 limosa, H., Ixxi. 

 contexta (?), H., Ixxi. 

 sp. n. (?) 



6. Microleus gracilis, H., Ixx, 



7. Lynghya muralis, H., lix. 



8. Calothrix. 



9. Polypothrix (?). 



Oscillatoria. — I have no doubt that with further research this list may 

 be indefinitely extended. The characters of some of the species are not 

 very distinctly marked ; and I imagine their nomenclature is not yet set- 

 tled. Certainly the description and figure of 0. autumnalis as given by 

 Hassall are very different from those in the Micrographic Dictionary. The 

 peculiar characteristic of this genus, from which its name is derived, is the 

 singular movements of the filaments. What the cause of these move- 

 ments is has been the subject of some speculation, but has not been de- 

 termined. No special organs of motion have been discovered. Whether 

 they are vital or merely mechanical phenomena, is at present impossible to 

 decide. I have seen them in plants which had been immersed many days 

 in Hantzsch's fluid still continuing, feebly but quite perceptibly. The 

 movements are of two kinds — oscillatory and progressive. In the first, 

 the filament, being apparently fixed at one end, sways backwards and for- 

 wards upon a centre like the pendulum of a clock, and it may either 

 remain in a state of rigidity, or may curve with a flexibility resembling 

 that of the long thin branch of a tree when agitated by the wind. The 

 other movement is one of direct progression. A filament will, after a period 

 of quiescence, begin to move forward, end on as it were, and having 



