FROM THE NORTH-WEST AMERICAN COAST. 159 
tain one ; for it occurs occasionally in Algw when developed under 
unusual circumstances; or it may arise from proliferous growth, 
after wounding at an early age. More specimens, and specimens 
of various ages, are required fully to establish this species. 
Of Hymenena latissima many specimens were collected, but 
comparatively few of them were of adult age. The younger are 
undistinguishable from some Nitophylla in structure, the ge- 
neric distinction not generally becoming obvious till fruit begins 
to be formed. Then the long lines of tetraspores are obviously 
separated by immersed and anastomosing veins, as in the original 
H. fissa, from which species and from H. fimbriata our plant is 
quite distinct. 
Of the other new species, Callophyllis flabellulata is remarkable 
for closely simulating Euthora cristata; Prionitis Lyallii for its 
extraordinary variations in ramification and size; and Callitham- 
nion subulatum for combining the characters of C. americanum 
and C. floccosum. 
The species peculiar to the North-west Coast of America are 
32, of which 7 are Melanosperms and 25 Rhodosperms, viz.— 
Cystophyllum Lepidium, P. § R. Rhodymenia pertusa, Ag. 
Phyllospora Menziesii, Ag. Cystoclonium gracilarioides, H. 
Nereocystis Lütkeanus, P. & R. Callophyllis flabellulata, H. 
Alaria marginata, P. & R. Constantinea Sitchensis, P. & R. 
Agarum fimbriatum, H. Gigartina mollis, Bail. & Harv. 
Laminaria apoda, H. Chondrus affinis, H. 
Ectocarpus oviger, H. Endocladia muricata, 4g. 
— Halosaccion Hydrophora, J. 4g. 
Rhodomela Larix, Ag. Prionites Lyallii, H. 
R. floccosa, 4g. P. lanceolata, H. 
R. Lyallii, H. Schizymenia Mertensiana, P. & R. 
Polysiphonia Californica, H. S. coccinea, H. 
P. senticulosa, H. Microcladia Coulteri, H. 
Amphiroa Californica, Dene. M. borealis, P. & R. 
Hymenena fimbriata, P. & R. Ptilota Californica, P. & R. 
H. latissima, H. Callithamnion subulatum, H. 
Rhabdonia Coulteri, H. 
The following, from among the peculiar North-west American 
species are “ represented ” by allied species in other seas, viz.— 
Phyllospora Menziesii, by Phyllospora comosa, in Australia. 
Alaria marginata, by Alarja esculenta, in Europe. 
Rhodomela Larix, by Rhodomela lycopodioides, in Europe. 
Hymenena fimbriata, by Hymenena fissa, at the Cape of Good Hope. 
Rhodymenia pertusa, by Rhodymenia polymorpha, in Australia. 
