OF NAIAS GRAMINEAj VAK. DELILEI. 



39 



but lie makes that of N. alaganensis mucli nearer to that 

 of N. flexilis than I find it to be in the Manchester plant. 

 A third type of spine is furnished by Naias minor, All. 

 {Caulinia fragilis, W.). This shows an advance upon the 

 basal arrangement of the spines of N. flexilis and N. gra- 

 minea, in being formed of more than three cells (see fig. 50). 

 The entire tooth stands much above the line of cells which 

 forms the margin of the leaf. 



Kg- 51. 

 Fig. 49. Fig. 50. 



Upon comparing these figures (which I have carefully 

 made from typical specimens) with those given by Braun 

 on p. 275_, vol. ii. of the 'Journal of Botany^ (1864) _, it will 

 be seen that my drawings present considerable variation 

 from his^ particularly in N. flexilis. It is possible that 

 Braun's figures were meant to be diagrammatic_, and 

 representative of groups rather than of species ; for con- 

 venience of reference I have reproduced them in Plate VI. 

 figs. 6-8. 



The other end of the series of types of spines is repre- 

 sented by the tooth of N. major, where there is not only a 

 multicellular base, but the spine itself is compound ; one 



