146 CONJUGATED. 



Zygnema quininum. Cells usually twice as long as broad. 

 Sporangia oval, and not usually producing any inflation of 

 the receiving cell. 



Hab. Cheshunt and its vicinity : A. H. H. At Hawk- 

 hurst ; in a pond in a cottage garden between Broom- 

 hill and Speldhurst ; and by the road-side near Black- 

 boy's toll gate : Mr. Jenner. Graham Castle : Major 

 Martin. 



" This common species was formerly (see f Annals and Ma- 

 gazine of Natural History,' vol. x. p. 35.) passed over by me 

 as a variety of Z. quininum) from which I am now perfectly 

 satisfied that it is specifically distinct. When a number of 

 cells unite in regular order with those of a neighbouring 

 filament, no inflation of any of these occurs ; but it fre- 

 quently happens that several adjoining cells of a filament for 

 some reason or other do not unite, although the remaining 

 ones in that filament do ; in which case, those which have not 

 yoked themselves swell up, assuming a moniliform appear- 

 ance, and at the same time frequently emit blind and irregular 

 processes or prolongations, by which the cells manifest the 

 strong tendency which they have to conjoin themselves, but 

 which some cause, not evident, would appear to have frus- 

 trated. In some specimens, the number of inflated cells and 

 blind processes is but small, while in others the elongated 

 cells are more numerous than those which have united in the 

 ordinary manner of the Zygnemata." MS. 



14. ZYGNEMA JESTIVUM Hass. 

 Plate XXVIII. Figs. 3, 4. 



Char. Filaments of less diameter than those of Z. varians. 

 Cells usually about four times as long as broad, but some- 

 times much longer, and occasionally shorter. Sporangia 

 oval, not producing any inflation of the cell in which they 

 are formed. 



Zygnema astivum Hassall, in Ann. Nat. Hist. vol. xi. p. 433. 



Hab. Cheshunt : A. H. H. Wadhurst ; and Bury, near 

 Arundel : Mr. Jenner. 



