378 DESMIDEiE. 



Hab. Bogs at Fisher's Castle ; Waterdown Forest ; Pilt- 

 down Common ; Cross in Hand, &c. : Mr. Jenner. 

 Dolgelly, Caermarthen, and Penzance : Mr. Ralfs. 

 Hiojh Beech : A. H. H. Aberdeen : Dr. Dickie. 



The fronds when empty are found to be minutely punc- 

 tate, the puncta being arranged in longitudinal rows. It 

 differs from Tetmemorus granulatus in its form altogether 

 and in its puncta arranged in longitudinal lines. 



2. Tetmemorus granulatus Ralfs. 

 Plate LXXXIX. Fi^. 6. 



*o' 



Char. Frond six or seven times as long as broad, tapering 

 both in front and lateral views, but slightly constricted 

 in the centre. Segments rounded at the extremities 

 and terminating in a colourless, projecting, lip-like pro- 

 cess, punctated. Puncta arranged in diagonal lines. 

 Granules in a row down the centre of the frond. 



Closterium granulatum Breb., in Menegh. Synop. Desmid. 

 p. 236. Tetmemorus granulatus Ralfs, in Annals of 

 Nat. Hist., vol. xiv. p. 257. pi. viii. fig. 2. T. granu- 

 latus Jenner, in Flora of Tunbridge Wells, p. 198. 



Hab. Bogs at Fisher's Castle ; Scrubbs, Colebrook Park, 

 Waterdown Forest; Ashdown Forest, and Cross in 

 Hand : Mr. Jenner. Dolgelly and Penzance : Mr. Ralfs. 

 High Beech : A. H. H. Aberdeen : Dr. Dickie. 



Tetmemorus granulatus differs from the preceding species 

 in several respects. In the form of the frond, which is alto- 

 gether different, being quadriform in T. Brebissoni, and fusi- 

 form in the present species, in the remarkable lip-like pro- 

 jection of the extremities of the segments, and in the arrange- 

 ment of the puncta in diagonal and not longitudinal lines. 

 Near the junction of the segments the puncta are observed 

 to be arranged in three or four transverse lines. 



This species has been found by Mr. Ralfs in a state of 

 conjugation, and with the sporangium formed similar to that 



