ALGÆ ANTARCTICA. 257 
of the frond, which is 4-5 inches long, and deeply cleft 
into 5-9 segments either radiating from a centre in a digi- 
tate manner, or springing like pinnules, from a lengthened 
rachis. Colour at the base brownish-red, becoming rosy 
upwards. 
20. Plocamium* Hookeri, Harv.; fronde anguste lineari carti- 
laginea compresso-plana decomposito-ramosa disticha, ra- 
mis primariis subdichotomis patentibus, secundariis alter- 
nis flexuosis alterné folia et ramulos emittentibus, foliis 
planis aveniis obliquis obovato-lanceolatis obtusis basi 
attenuatis, nunc cultratis integerrimis v. margine exteriore 
crenatis, ramulis linearibus alterné et secundé pectinato- 
multifidis, stichidiis lateralibus densé fasciculatis brevibus 
digitatis laciniis obtusis simplicibus, coccidiis lateralibus 
sessilibus sparsis. 
Han. Christmas Harbour, Kerguelen's Land. 
Frond 8-10 inches long, not quite aline in diameter, plano- 
compressed, cartilaginous, very much branched in an irregular 
manner between dichotomous and pinnate ; the main branches 
spreading widely. Lesser branches with a linear outline, 
alternate, flexuose, furnished throughout both with flattened 
nerveless leaves, and with decompound ramuli, the larger 
of which resemble the branches in bearing a second set of 
leaves and branchlets; the ultimate divisions being generally 
secund and pectinate, as in P. coccineum. The leaves, which 
are peculiar to this species and at once distinguish it from 
every other, are about 4 an inch long, and from 1j to 3 
lines broad, narrow-obovate or lanceolate in shape, obtuse, 
nerveless and generally quite entire, but sometimes their 
Outer margin is slightly crenate. They are always more or 
* Plocamium Magellanicum, H. and H. (Thammophora Magellanica, 
Mont.) was found abundantly at Kerguelen's Land, the Falkland Islands, 
and Cape Horn. Most of our very numerous specimens are covered with 
Coceidia, but not one solitary individual bears stichidia, which is the 
more remarkable because, in other species of the genus, this latter descrip- 
tion of fruit is much most generally produced. ái 
VOL. IV. U 
