NATURAL HISTORY. 
ternally with transverse parallel strie.—They have 
all un oscillating motion, whence the name is derived. 
1. Growing in fresh water. 
1. O. Nigra. Dillw. t.64. (Conr, Font1- 
NALIS. In clear streams, attached to submersed 
stones, 
2. O. Limosa. Dillw.t.20. (Conr, Limo- 
sa.) Ditto. 
2. Marine. 
3. O. ScorpuLtorum. Dillw. Suppl. t. A. 
E, Bot. t. 2171. (Conr, ScopuLtorum.) 
On the ground—damp walls, &c. 
4, O. Moranis. Dillw.t.7, E. Bot, t. 1554, 
Common at all seasons, on walks, damp walls, &c. 
VAVCHERIA, 
With irregularly branched filaments—the fructifi- 
cation a granular mass within the frond, and external 
vesicles (frequently with hooked processes contiguous 
to them.) 
1. Vesicles solitary. 
lL V. Dititwyni. ODillw. t. 16. (Conr, 
