7. Melobesia microspora sp. n. 
Frondes suborbiculares, sepe confluentes, 1—2 mm diametro, excepta parte 
marginali polystromaticæ, e filis verticalibus usque ad 7-cellularibus compositæ; 
cellulis filorum 6—8 „ latis, diametro vulgo 1—2-plo longioribus, cellulis strati 
basalis plerumque brevioribus. Cellule corticales desunt. — Conceptacula nume- 
rosa contigua vel subcontigua. — Conceptacula sporangifera depresso-hemisphærica 
vel conica, diametro 120—140 y, ostiolo vix papilloso, medio nonnunquam columella 
munita. Sporangia parva, 17—24 „ longa. (9—)11—12(—16) » lata, semper 4-partita. 
Sub conceptaculis 1—4 strata cellularum vegetativarum. — Conceptacula mascula 
parva, paulo prominula vel omnino immersa. Spermatangia elongata vel clavata, 
fundum planum conceptaculi investientia. Spermatia lineari-clavata, nonnunquam 
leniter curvata, c. 64 longa, 2 „ lata. — Conceptacula feminea ut videtur forma 
structuraque conc. sporangiferis similia. — Hab. in fronde Furcellarie fastigiate. 
The species here described has only been met with once, viz. on a specimen 
dredged in the bay of Aarhus. The specimens were determined by FosLie as Melo- 
besia Lejolisii Rosan. forma, but as will be seen from the description given here, 
it is very different from that species, particularly in the structure of the frond and 
the small dimensions of the sporangia. 
The greater part of the frond is polystromatic; only the marginal part is 
monostromatic, but it is early divided by horizontal walls, and the frond is then 
composed of vertical filaments composed of from two to seven or eight cells. These 
filaments are usually 6—8 » broad and consist of cells of varying length, usually 
1 to 2 times as long as broad. The cells of the basal layer are rather varying in 
height, but they are usually lower than broad. There is thus no contrast between 
the basal layer and the perithallium. Seen from above, the cells of the basal layer 
show a breadth of 5—8 », about the same length or a little more, and appear to be 
frequently connected by lateral fusions (fig. 176 C). Such fusions may also occur 
between cells above the basal layer, but transversal pores (secondary) nowhere 
occur. It is remarkable that cortical cells as those characteristic of the other Melobesia 
species do not occur. When seen from above, the superficial cells present them- 
selves as nearly quadratic cells arranged in rows, but no small cells cut off from 
them appear, not even after staining with hematoxyline, by which treatment the 
walls of all the outer cells and the cuticle are very intensely stained. Hair-cells 
were not observed. 
The conceptacles are numerous, occupying most-part of the crust, frequently 
contiguous, giving the frond a verrucose aspect. TheZsporangial conceptacles are 
depressed hemispherical or more rarely low conical. A more or less developed 
central narrow columella is not infrequently present. The sporangia which do not 
occupy the centre of the conceptacle are remarkably small; they are always four- 
parted, the three septa approaching each other in the middle of the sporangium 
(fig. 177 A). When seen from above, the small ostiole is seen to be surrounded by 
