

156 CONJUGATEiE. 



I have only once met with this. If a condition of any, it 

 must be of the preceding species. 



b. S2)orangia formed in every cell, 



34. Zygnema mirabile Hass, 



Plate XXXV. Figs. 1, 2, 3. 



C%«?\ Filaments equal to those of Z. commune in diameter. 

 Cells ahout six times as long as hroad. Sporangia oval, at 

 first much elongated, and finally producing a slight in- 

 flation of the cells. 



Z, mirabile Hassall, MSS. 



' Hab. Cheshunt and its vicinity ; A, H. H. In the pond 

 P^^"^ between Tunbridge Wells Common and the Hurst 



'y^ f\^^ . Wood ; in a pond at Burwash : Mr, Jenner, 



This remarkable Zygnema I have repeatedly met with in 

 the state in which I have described it, and which I believe to 

 ' be its perfect condition. Mr. Jenner states that he is con- 



v-^^'-"^ vinced that the cells are united, but that the connectino- 

 /^^ tubes are so frail as usually to be destroyed before the 

 j^/^u specimen is examined. Mr. Jenner's observation, however, I 

 — feel assured applies not to Z. mirabile, but to some other 



^ species ; for had the cells at any period been united, they 



-/■ — . would have been clearly indicated, even in the absence of the 

 ^h"^' connecting tubes, by the occurrence of empty cells in number 

 '^li<^- equal to those which contained sporangia. Now I have said 

 .^"^ that in this species all the cells contain sporangia. 



' ^ ti^'^y J ]ir^^ '^ ** Extremities q/* cells inverted, 



a. Spires tico. 



35. Zygnema Hassallii Jenner. 



Plate XXXVI. Figs. 4, 5. 



Char. Filaments of nearly the same diameter as those of 

 Zygnema Grevilleanum. Cells five or six times as long 

 as broad. Spires two, laxly disposed, and crossiiig each 



