180 ARCHER, ON TWO NEW SPECIES OF COSMARIUM. 
cato-rotund; no clear space with moving granules at the 
extremities; zygospore quadrangular, oblong, compressed, 
angles mamillate, extremities nipple-like. 
Locality —Featherbed Bog, and near Lough Bray, con- 
jugated. 
General Description.— Frond very minute, about one 
third longer than broad, sub-elliptic, sides somewhat barrel- 
shaped, ends truncato-rotund; endochrome dense, a single 
large (amylaceous) granule in each half, and showing two or 
three indistinct longitudinal “ fillets,’ and an instinct, pale 
central band; no moving granules at the extremities; end 
view, orbicular or very broadly elliptic; empty cell-wall 
colourless, without markings. Zygospore in front-view quad- 
rangular, oblong, about 10:6 longer than broad, compressed, 
margins somewhat concave at the centre, angles produced, 
mamillate, nipple-like at the extremities; contents sparing, 
scattered ; in side view elongate, often with a slight con- 
cavity at each side, ends rounded, extremities nipple-like ; 
in end view, ovate, accuminate, extremities nipple-hke. The 
empty parent-cell-membranes persistent at each end of the 
zygospore. If, as is mostly the case, the parent-cells con- 
jugate in a parallel position, the zygospore possesses a regular 
cushion-like figure, all its angles lying in the same plane 
(Fig. 39). But if, during the conjugation, the parent-cells 
lie at right angles to each other, there is then a correspond- 
ing twist in the form of the zygospore, and in this case the 
angles at. one of its ends lie in a plane at right angles to 
those of the other. Apparently from a similar cause, any 
intermediate degree of relationship in this regard may thus 
take place. Misshapen or irregularly contorted zygospores 
occasionally, but exceptionally occur, in which one of the 
corners may be inordinately drawn out, or the usual relative 
proportions of length, breadth, and depth become partially or 
locally interfered with. The mamillate form of the angles, 
and their nipple-lhke extremities, are maintained, however, 
in all cases (figs. 39—44). The conjugating, as well as 
dividing, cells are surrounded by a distinctly bounded gela- 
tinous investment, which afterwards disappears. 
Measurements. —Leneth, +s'zz3 breadth, 5,5; depth, 
+75 of an inch. 
Length of zygospore, -1, to ;14,; breadth, +3. 
Pl. VI, Fig. 34, frond with endochrome; 35, dividing 
frond; 36—88, commencing conjugation; 39, front view of 
zygospore; 40, side view of same; 4], end view of same; 
42—44,, variously twisted zygospores. 
Affi nities and differences.—I do not doubt but there might 
