CHAETOPHORA 218 
In brooks, chiefly attached to pebbles and rocks. 
MassacuusETTS: Middlesex Fells, July (449). 
New York: Bronx Park, May (372); Van Cortlandt Park, 
May (603). 
New Jersey: Hudson Heights, May (434); Demarest, Oc- 
tober (507). 
Though sometimes appearing to be very closely related to C. 
elegans, nevertheless, in general this species is very distinct from 
that form. It usually has a darker green color, and firmer more 
resistant gelatinous substance ; in fact it is often a difficult matter 
to separate or crush the closely packed filaments. Though size is 
a very variable quantity, in general the filaments of C. pisiformis 
are more slender than those of C. elegans, the branches are always 
erect, and the terminal branchlets usually less numerous. This 
species appears to be less inclined to grow in quiet waters; we 
have nearly always found it in a strong current. 
3. Chaetophora attenuata sp. nov. 
Colonies globose or slightly verrucose, solitary, 2-5 mm 
diameter, bright green, involved in dense and very resistant nati 
ulate at summit ; terminal branchlets finely pointed or setiferous ; 
cells of the main filament 5—5.5 in diameter, 5-10 times as long; 
branch-bearing cells broad and often bifurcated at the top (X. 39). 
On rocks and pebbles at the edge of ponds. 
CONNECTICUT : Plymouth, reservoir, September (491, type). 
New JERSEY: Greenwood Lake, September (466). 
This species, like C. pzsiformzs, possesses a more resistant gelat- 
inous investment, and a stricter habit of branching than C. elegans, 
but its flaments are much finer and more attenuated than those 
of either of the other species. It is characterized by great regularity 
in its branching above, and by abundant rhizoid development, 
rhizoids being pushed out even below the palmelloid basal cells. 
This appears to be a summer form, for all traces of it disappear 
before the end of October, and none appeared in the spring up to 
the middle of May. 
It is a curious fact that Chactophora pisiformis and C. attenuata 
are at times infested by rotifers, while C. elegans seems never to be 
