53 
Faminy X. SCYTONEMACEA, Rabh.. 
; Filaments with lateral ramifications, in which some of the cells 
change into heterocysts.—Cooke’s British Freshwater Alge, 264. 
This family is divisible into two sections, according to the direction 
of the multiplication of the cells.—Cooke; l.c. 
SCYTONEMA, Ag. 
given off at aright angle. Heterocysts scattered here and there in 
the trichome, without any evident relation to the ramifications.— 
Cooke’s British Freshwater Algw, 264. - 
S. subtile, Moebius (n. sp.). This alga is set down by Prof. 
Moebius as a new species. Heremarks :—* This alga, which seems to me 
not to agree with any of the described species, belongs to the section 
__ _Euseytonema, Born. et. Flah., and forms no coherent layer, but occurs 
_ In isolated threads amongst other alge in water. (Fig. 50: a, frag- 
ment of a filament with branching; b, end of a branch.) The threads 
the cells are only 2-4 p thick, twice to three times as long, an 
_¢ylindrieal only ; the cells adjacent to the terminal cell are short and 
_ dise-shap ndochrome several vacuoles are generally to b 
: ily n many cells in the centre a d y (nucleus ?) 
oe given off are perceptibly thinner, but as they proceed are only 
Slightly thinner than the main threads.” 
Hab. : ‘Burpengary, Thos. L. Bancroft. 
oe append -—“Species sectionis Euseytonematis, Born. et lah., filis 
see, oe. men Tab, inter alias algas aque dulcis 
ustralie (Burpengary).”’ (Species belonging to the section 
vat r h. Threads long and 8 attered, each 
: 8 
= serhae cell being dise-shaped, and the others 2-3 times longer than. 
thi diameter’ sheath hyaline, lamellose, 12-17 » thick, heterocysts 4 » 
ck, 10-14 » long. Spores not seen.” 
Fairy XI. NOSTOCEA, Kuetz. 
___ Trichomes furnished with het sts, involved in a very copious 
_Belatin, more or a vs ; oO . ‘fluent, which is collected into @ 
=. ously expanded or very often indefinite thallus, or rarely. with a 
Brune’ quickly dissolved, sub-solitary.—Borzi Alg. Fico ; Cookes 
= h Freshwater Alge, 224. ° : 
