ON NAIAS GRAMINEA DEL., VAR. DELILEI MAGNUS. 311 
of tooth from the characteristic tooth of N. flewilis. Cesati gives 
figures of the dentition of these two species in Plate II. of ‘Linnea,’ 
vol. xxxvi.; but he makes that of N. alaganensis much 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 advane 
upon the basal arrangement of the spines of N. /lewilis 
d N. graminea, in being formed of more than three 
Upon comparing these figures (which I have care- 
fully made from typical specimens) with those given by 
Braun on p. 275, vol. ii. of this Journal, it will 
that my drawings present considerable variation from 
ly in N. flewilis. It is possible that 
Braun’s figures were meant to be diagramatic, and 
representative of groups rather than of species; for 
convenience of reference I have reproduced them in 
Plate 251, figs. 6 to 8 
The other end of the series of types of spines is represented 
by the tooth of N. major, where there is not only a multicellular 
base, but the spine itself is compound; one terminal dark brown 
cell resting upon several elongate dark brown cells, the whole 
orming ery conspicuous tooth 
standing well out from the plane of 
late Dr. Wirtgen’s specimens from 
the mouth of the Moselle, near 
Coblentz. 
have been drawn from spines on the 
edge of the middle portion of the leaf. 
Their shape is constant on the sides 
of the lamina, but they become longer 
on the sheath, and at the apex of the 
leaf. 
