BRITISH DESAIIDIE.E. 7^ 



which separate it from them are deep, and directed inwards and 

 downwards. 



In the second section the fronds are more minute and scarcely 

 visible to the naked eye ; the segments are less decidedly lobed, but 

 the margin is crenate or sinuated, and the terminal portion unites 

 with the basal by a neck-like contraction of the segment, and is there- 

 fore never included within a notch ; the corners are rounded. The 

 outline of a segment has some resemblance to that of a decanter or 

 water-bottle. 



The third section contains those species which do not well agree 

 with those in the preceding ones. The fronds are extremely minute, 

 the segments are generally still less lobed than in the last, and the 

 form of the front view is more irregular, and frequently differs in 

 having a process or an acute angle at either the corners or the sides 

 of the terminal portion. 



Several species have been observed in a conjugated state. 



* Segments of the frond deeply lobed; the terminal lobe cuneate, and 

 partly included in a notch formed by the projection of the lateral 

 lobes. 



1. E. verrncosum (Elir.) ; frond rough with conic granules ; the seg- 

 ments three-lobed ; lobes broadly cuneate with a broad shallow 

 notch. 



Euastriim verrucosum, Ehr. Abh. d. Bert. Ak.Tp. 247 (1833) ; Infus. p. 162. 



t. 12. f. 5. Ralfs, Annals of Nat. Hist. v. 14. p. 189. t. 6. f. 3 ; Trans. 



of Bot. Soc. of Edin. v. 2. p. 125. t. 10. bass. Brit. Alg. p. 3/9. 



Kiltz. Phycologia Germanica, p. 135. 

 Cosmarium verrucosum, Menegh. Synoj). Desndd. in Linncea 1844, p. 222. 



In pools. Chesliunt, 3Ir. Hassall. Weston Bogs near Southampton ; Rust- 

 hall Common and elsewhere near Tunbridge Wells ; Ashdown Forest, Sussex ; 

 Hampshire ; and Reigate, Surrey, Mr. Jenner. Penzance and Dolgelley, /. R. 

 Near Ambleside, Westmoreland, Mr. Sidebothani. Aberdeenshire and Banff- 

 shire, Mr. P. Grant. 



Germany, Ehrenberg, Kutzing. Falaise, Brebisson. New York, Bailey. 



Frond rather longer than broad, angular ; the segments, which slightly 

 diverge from each other, are deeply three-lobed ; the lobes are broad, cuneate, 

 with a broad shallow notch. Surface of the frond furnished with numerous 

 conic granules, which give the margins a dentated appearance, especially the 

 more prominent parts : each segment has two circular prominences near the 

 base ; on these the granules form two or three concentric circles with a gra- 

 nule in the centre ; the terminal lobe has two similar but smaller prominences. 



