RED SEAWEEDS 95 
with numerous forward-pointing branchlets, which in turn have spine- 
like ramuli of various lengths; frond flat, broadly spreading; dark red. 
It is common at all seasons on the California coast. (Plate- XXXVI.) 
Genus Halosaccion 
HH. ramentaceum. Fronds brownish-purple, six to fourteen inches 
long, coarse and cartilaginous, cylindrical, hollow, compressed, attenu- 
ated at the base; more or less covered with simple or forked hollow 
branches half the size of the main stem. In exposed pools the plants are 
short and densely branched; in sheltered places they are larger and 
more delicate in texture. They are common on the northern New Eng- 
land and northern California coasts. (Plate XXXVL.) 
SUBORDER RHIZOPHYLLIDEE 
Genus Polyides 
P. rotundus. Frond three to six inches high, cylindrical, cartilagi- 
nous, repeatedly forked, ends obtuse ; spore-masses form numerouslighter- 
colored excrescences on the upper divisions of the frond 3 dark red. 
Common from New York northward, in deep pools and washed ashore. 
(Plate XXXVI.) 
SUBORDER SQUAMARIEE 
GEnus Peyssonnelia 
P. Dubyi. Frond completely adherent to the rock or stone on which 
it grows; color dark purple; somewhat calcareous ; redder and thicker 
than next species. It is found at low-water mark or in deep water on 
the northern New England and northern California coasts. 
Genus Petrocelis 
P. erwenta. Frond closely adherent, forming dark-purple velvety 
patches of indefinite outline on rocks and stones. Common north of 
Cape Cod. 
Genus Hildenbrandtia 
Hi. rosea. Forms continuous pink incrustations of considerable ex- 
tent on stones and rocks at low-water mark. Common everywhere. 
SUBORDER CORALLINEE 
The genera of this suborder are characterized by a calcareous 
or stony incrustation of the fronds, which gives them the appear- 
ance of corals. Most of the species are tropical. 
