( 3 ) 
with a reticulated membrane, quite distinct from N. onentalis 
Allen ; indeed N. Japonica Allen is to be included in this group, 
it was erroneously referred by me to the oligospira section, but 
later collections show distinctly clustered oogonia; the cells of 
the coronula are however elongated, placing it in alliance with 
the true N. polglochin series, which is separated by coronula 
characteristics from our N. orientalis, which has a short coronula. 
Illustrations of these new Japanese species will follow later when 
a series of plates can be prepared. 
io. Nitella paucicostata sp. nov. Monarthrodactyla, fur- 
cata, homoeophylla, gymnocarpa, dioica, apiculata, membrane of 
oospore granulated. (Series oi N. opaca Ag.) 
Plant 2 to 6 inches high, branched from the base, diffuse and 
flaccid. Verticils remote, at length becoming crowded above, 
bearing about eight leaves and usually short peduncles (shoots) 
which fruit abundantly when very short, close to the base of the 
verticils. Leaves once divided, often long and slender (bright 
green and flaccid in our specimens); terminal segments three, 
about as long as the first segment of leaf, abruptly pointed (like 
N. opaca). Stem 366 to 500 in diameter; leaf first segment, 146 
to 425 usually 300 diameter; second segment, 170 to 220 usually 
170 diameter. Fruit clustered at the node of the leaf; oogonia 
2—3., globular ; coronula minute, evanescent; oospore about 408 
long by 340 broad (400 by 340, 408 by 380, 440 by 374, 440 by 
360, 440 by 370); membrane of oospore very minutely roughened ; 
ridges only 4 (or 5) ; antheridia 488 in diameter. 
This species was collected near Tokio, and adds another 
to the multiplying opaca series. In reviewing the species of 
this series which have roughened oospores, we find that only N. 
obtusa Allen has apiculate leaves ; the others have acuminate 
leaves. From N. obtusa the Japanese species is easily distin¬ 
guished by its small size and small leaves and by its smaller 
oospore with very few striae or ridges. 
