CH^TOPHORA. 125 



Through Draparnaldia tennis and D. nana there is an 

 easy and natural transition to this genus, 



Imbedded in the gelatinous matrix, are usually, in the 

 older specimens, a number of stony particles ; these have been 

 supposed to be in some way or other connected with repro- 

 duction. Vaucher regards them as the ruptured cells of the 

 plant, and destined to reproduce the species. 



1. CHJETOPHORA DILATATA Hass. 

 Plate XIII. Fig. 2. 



Char. Filaments much branched, fastigiate. Extremities 

 dilated. 



Hob. Ireland : Mr. Moore. 



This species I discovered accidentally, mixed up with a 

 specimen of Nostoc muscorum. It is very remarkable. 



2. CH^ETOPHORA ENDIVLZEFOLIA Ag. 

 Plate IX. Figs. 1, 2. 



Char. Mucous matrix somewhat compressed) sub-dichoto- 

 mously branched. Primary branches frequently parallel ; 

 apices of ultimate ramuli ciliated. 



Batrachospermum fasciculatum Vaucher, Hist, des Conf. 

 d'Eau douce, p. 116. pi. xiii. fig. 1.; Harvey in Hooker's 

 Brit. Flor. ii. p. 389. Ulva incrassata, E. Bot. 967. 

 Chcetophora endivicefolia Harv. in Manual, p. 122. 



Hob. Common in streams. 



" This Batrachospermum is more rare than the preceding 

 species B. moniliforme 9 B. plumosum, and B. glomeratum : it 

 is met with in slowly running waters, covering stones, to which 

 it is attached, under the form of a little green protuberance 

 irregularly lobed at its extremities. It is but little more 

 than a few lines in length, and about half as broad. It can 

 scarcely be distinguished with the unaided sight, but with 

 the microscope it appears curiously composed. If but a very 



