131 
growing at its extreme southern limit; probably farther north and 
east it would be found more fully developed. 
Ulva percursa^ Ag,, (^Enteromorpha percursa, J, Ag.) Growing 
in upper tide-pools at Kennebunkport, Maine, Hampton, N. H., and 
Cohasset, Mass., and probably common in tide-pools and marshy 
places along the coast. It is undistinguishable by the naked eye 
from^ the various Ulvce and Rhizodonia found in similar localities, 
but is easily recognized on microscopic examination by the frond 
composed of two longitudinal series of symmetrical cells. It is figured 
in Areschoug, Phycae Scandinavicae Marinae, Part 2, Plate ii. A, 
Ulva marginata, Lejolis. {^Enteromorpha marginata, J. A g,) 
Weymouth and Quincy, Mass., growing on woodwork; distinguished 
by its dark green, narrow, slightly branched, flattened frond, com- 
posed of a few longitudinal series of small, elongated cells, the 
marginal series differing somewhat in depth of color from the central. 
This is the Ulva referred to in my note in the Bulletin of March, 
1884. 
Ulva aureola^ Ag. {Enteromorpha aureola, Kiitz.) Growing in 
small quantities among Ulvce^ Lynghm, Rhizodonia^ etc., in the 
marshes at Hampton^ N. H. The cells, which are arranged in longi- 
tudinal series, look like a Gtceocapsa, Figured in Hauck, Die 
Meeresalgen Deutschlands, Fig. 190. 
Myrioncma orbicidare, J. Ag. On Zostera marina, Kennebunk- 
port and Hampton. Differs from the common M. vtdgare, Thuret, 
by the presence of pecuUar, saccate, hair-like growths, in addition to 
the usual hairs and pamphyses. Figured in Hauck, Meeresalgen, 
F'g- 132. I am indebted to Prof. J. G. Agardh for the identification 
of this species, and for valuable assistance in determining various 
forms of the Ulvace^. 
Porphyra cocdnea, J. Ag. On Desmarestia aculeata, Lamour., at 
Hampton, N. H. A very delicate alga, with a thinner frond and 
niuch smaller cells than any other American Porphyra. I found it 
only once, a floating plant of Desmerestia being pretty well covered 
with the delicate fronds, which, when lifted out of the water, collapsed 
like one of the finer Callithamnions. Figured in Agardh, Till 
Algernes Systematik, vi., Plate ii.. Figs. 41-43. 
Porphyra miniata, Ag. The Nahant plant which I mentioned in 
the Bulletin for May, 1882, under the name of P, leucosHca^ Thuret, 
seems to belong rather to this species. I have since found it at 
Kennebunkport and at Hampton, at both of which places it seems to 
be not uncommon in the summer, growing on other alg^e, or washed 
up from below low-water mark. The antheridia do not form patches 
of any considerable size, but are scattered va groups of a few cells 
throughout the frond. This is a characteristic arctic species, and adds 
another to the list of extreme northern species that have been found 
extending quite a distance south on the American coast. Its occur- 
fence in the same locality with Dasya elegans, Ag., is a curious 
^^stance of the meeting of northern and southern forms in Massa- 
chusetts Bay. P. miniata is figured in Agardh, Till Algernes Sys- 
tematik, vi., Plate ii.. Figs. 44-48. 
I have received what appears to be the true P. kucosticta from 
