280 THE ANTARCTIC MANUAL. 
3. Leaving the Floridean zone, we come to the zone of Macro- 
cystis, hidden among the roots and borne upon the fronds of which is 
an abundant associated fauna. A classical passage in the ‘ Voyage 
of the Beagle’ (chap. xi.) records Darwin’s vivid impression of this 
fauna of the kelp, as he saw it in the Straits of Magellan. This kelp 
fauna deserves careful study, not only for its abundance and com- 
parative accessibility, but also for the interest that would attach to 
its comparative study at different points along the vast range of dis- 
tribution of the kelp, from the Antarctic Ocean all along the western 
coasts of America to Behring Sea. 
The thirty-fathom long fronds of Macrocystis are anchored to 
stones in four to six fathoms of water. On the floating fronds creeps 
a little white Holothurian, Pentactella laevigata, Verr. (also Patago- 
gonian), the little Halicarcinus, the Isopods already mentioned, and 
several Limpets, e.g. Patella kerguelensis, Smith, P. fuegensis, Rve, 
and especially P. (Nacella) mytilina, Gmel. (the two last being Ma- 
gellan and Falkland Islands species); also Admuete (?) limnerformis, 
Smith, Littorina setosa, Smith, Scissurella supraplicata, Smith, and 
others. Bryozoa, especially Tudulipora organizans, Busk (as at the 
Falklands), and 7. stellata, Busk, also Lepralia Katoni, Busk, Idmonea 
marionensis, Busk (also at Marion Island), etc., cover the fronds, 
tagether with the Hydroid colonies of Campanularia cylindrica, Allm., 
and Hypanthea repens, Alm. On the roots and stems grow Diachoris 
magellanica, Busk, Actinopsis rosea, Studer, and various compound 
Ascidians, Amaroucium variabile, Herdm., Colella concreta, Herdwm., 
Polyclinum pyriforme, Herdm. Among the tangled roots lives a 
still richer fauna, of which the following are examples :—Mytilus 
magellanicus, Chemn., numerous Pycnogons, Nymphon antarcticum, 
N. brevicaudatum, Tanystylum styligerum, all described by Miers ; 
various worms, e.g. Neottts antarctica, M‘Int., Nereis eatont, Amphi- 
trite kerguelensis, M‘TInt., and a Serpula, said to be identical with 
S. narconensis, Baird; also many star-fish and brittle-stars, e.g. 
Amphiura Studeri, Lym., Ophioglypha hexactis, Smith, Asterias meri- 
dionalis, Perrier, A. perrieri, Smith, Pedicellaster scaber, Smith, 
Pteraster afinis, Smith (very similar to P. dane, Verrill, said to be 
from Rio Janeiro), and again the remarkable Luidia-like Leptoptychaster 
kerguelensis, Smith. 
Less closely associated with the kelp, but occurring in the same 
zone, are many other forms, individually numerous, whose dull 
coloration and, in the case of the Molluscs, ill-calcified shells and 
thickened epidermis, are in conformity with their muddy habitat and 
in contrast with the brighter fauna of the Floridean zone. We have 
