60 
CLASS I.— ORDER I. 
IVORY. 
1. Crxsia eburnea . Upright, articulated and branch- 
ing; cells alternate, truncated, and slightly pro- 
jecting ; ovaria gibbous. 
European seas. 
CILIATED. 
2. Crisia ciliata . Cells almost lateral, alternate ; 
the opening large and oblique, garnished with nume- 
rous hairs unequal in length. 
European seas. 
hairy. 
3. Crisia pilosa. Stem upright and dichotomous, 
cells oblique ; the opening garnished with one or two 
long flexible hairs. 
Mediterranean. 
RUGGED. 
4. Crisia scruposa. Rampant and dichotomous; 
cells united and alternate : the opening oval, and bare. 
Seas of Europe, Asia, and America. 
THORNY. 
5. Crisia muricata. Stem articulated and dichoto- 
mous. Cells alternate, and garnished on their upper 
part with some sharp tubercles ; the opening toothed ; 
teeth silky. Colour, a dull white ; height about one 
centimetre. 
On the Fucus Horneri in the seas of Japan. 
rampant. 
6. Crisia reptans . Articulated, dichotomous, and 
