342 
sporangia open by a transversal slit in the 
upper part ofthe sporangium. The disporangia 
have been met with in May to July, the tetra- 
sporangia in June to October. 
The antheridial clusters have been describ- 
ed and figured by Kyrın (1907, p. 169, fig. 
35b). They are usually arranged in a row on 
the upper side of the upper pinnulæ, often on 
the lowermost 4—6 joints, but they may also 
be borne on branches of penultimate order. 
On each joint one to three clusters are to be 
found. Even when seated very densely they 
are never fused together as in certain other 
species. The clusters consist in a usually some- 
what curved axis composed of 3 or 4 cells 
å which are almost isodiametrical and bear each 
Callithamnion ee ona In A a! and a number of antheridia mostly on the! convex 
a? the two auxiliary mother-cells; 1, 2, 3, c, the Side turning downwards. The antheridia are 
RL hey: were pie 
mother-cells a? is wanting. A 350:1. B 270: 1. 5 with in July and September. 
Buffham has described and figured the 
antheridial clusters in Call. byssoideum (1884, p. 341, pl. X figs. 4, 5); they agree 
with those of C. Furcellarie by the position and the structure of the axes, but they 
seem to differ, according to BATTERS, by the antheridia being developed equally on 
all sides of the cluster and 
by being “very elongated”. 
— According to Kürzıns 
(Tab. phyc. Vol. 12 pl. 8), 
the antheridial clusters of 
C. byssoides are, at any 
rate in great part, axillary. 
The species of KÜTZING 
seems, however, to be very 
different not only from our 
species but also from Har- 
vEy’s by its much corticated 
main axes. — The antheri- 
dial clusters of C. byssoides Callithamnion Furcellarie. ine SE From Hirsholm. 200: 1. 
Börgs. from the Danish 
West Indies (F. BoBGEsen, Mar. Alg. Dan. W. Ind. 1917 (Dansk Bot. Ark. III, p. 218, 
Fig. 207) are also different, being cushions consisting “of a system of short (bran- 
ched) branchlets in which the uppermost cells are the antheridia”. They may some- 
