190 NEMATOPHYCE^E. 



Stigeocloniunx protensum. (Dillw.) Kutz. Tab. Phyc.ui.,t. 8, /. 2. 



Pale green, csespitose, slender ; filaments and branches long- 

 drawn out ; cells almost cylindrical, equal or twice as long as 

 their diameter ; terminal cell extended into a colourless bristle ; 

 branches usually scattered, rarely in pairs, with the extremities 

 cuspidate, piliferous. 



SIZE. Cells '015 mm. diam. 



Kabh. Alg. Eur. iii., 378. 



Draparnaldia condensata, Hass. Alg. 122, t. 11, f. 1. Ann. 

 Nat. Hist, xi., 429. 



Conferva protensa, Dillw. Conf. t. 67. Gray. Arr. i., 303. 



In slow streams. 



Plate LXX1V. jig. 1. Filament of Stigeoclonium protensum. a, 

 zoospores X 400 diam. ; b, branchlet of form called S. irreyulare X 

 400 diam. 



Stigeoclonium nanum. (Dillw.) Kutz. Spec. p. 352. 



Filaments alternately branched ; branches abbreviated, a 

 little attenuated upwards, obtuse, not piliferous ; cells equal or 

 a little shorter than their diameter, in the upper part equal. 



SIZE. Cells '008 mm. diam. 



Kabh. Alg. Eur. iii., 380. 



Draparnaldia nana, Hass. Alg. 124, t. 10, f. 3. 

 Draparnaldia sparse^ Hass. Ann. Nat. Hist, xi., 428. 

 Conferva nana, Dillw. Conf. t. 30. 



In streams (the Wye). 



The following are Dillwyn's remarks on this species : " The minute- 

 ness of the filaments, which in length seldom much exceeded a line, 

 prevented me from ascertaining their nature so fully as I could have 

 wished. Their colour is pale brown, tinged with green, sub-diaphanous 

 under the microscope. They appear to consist of a single stem, beset 

 at uncertain distances with alternate branches, which are again clothed 

 with short, simple, solitary ramuli, placed at small distances from each 

 other, most commonly alternate, although sometimes two or more 

 together are disposed on the same side. All of them are finely acumi- 

 nated; the dissepiments are very apparent, and divide the filament into 

 joints, all of equal size, of which the length is about double the thick- 

 ness. To the naked eye this plant appears, when taken from the water, 

 like a mere mass of decaying vegetable matter. Its extreme minuteness 

 might fairly induce a suspicion whether it is in reality anything more 

 than the seedling of some known Conferva. It adheres to either glass 



*o 



or paper." 



Plate LXXIV. j)g. 2. Filament of Stigeoclonium nanum X 400 

 diam., figured from Dillwyn's original specimen. 



