80 MARINE ALG 
a wide-forking manner; sometimes a branch will divide into several 
parts at the same point; color dark brown or purple. It is found, in 
summer only, from Long Island Sound northward, growing on smooth 
rocks which are exposed to the action of the waves. 
GEenus Liagora 
Fronds filamentous; branching regularly in a forking manner 
to the very top, forming thick bunches; slightly incrusted with 
lime, yet somewhat viscid. It is found in Florida and California, 
and abounds in tropical waters. 
SUBORDER CHETANGIEE 
Genus Scinaia 
S. furcellata. Frond cylindrical, one eighth of an inch in diameter, 
tapering at base, sometimes constricted at intervals, regularly and sev- 
eral times forked, ending in short divisions; branches of same length, 
giving a level top; two to four inches high; lake-red. When pressed 
the axis is visible, giving the appearance of a flat frond with a midrib. 
This species is found in summer only, washed ashore from Cape Cod 
SviLy and on the California coast. It is not common. (Plate 
SUBORDER GELIDIEE 
Genus Gelidium 
G. corneum. Frond flat and horny, one inch to four inches high, 
narrow, erect, branched several times in the same plane; ultimate 
branchlets club-shaped, or swollen at the tips with masses of spores; 
color purple-red. It grows in tufts on mud-covered rocks, and on alge 
at low-water mark. The typical form is found in Florida and on the 
Pacific coast. Smaller plants are found all along the Atlantic shore. It 
is an extremely variable plant, and 1s often difficult to distinguish on this 
account. (Plate XVII.) 
ORDER GIGARTINACEZ 
Genus Chondrus 
Carrageen or Irish moss. 
C. crispus. Frond begins with flattened stem, which divides and 
subdivides many times in a broad-forked, fan-like manner; varies 
greatly in length and breadth of divisions, also in size and color, accord- 
ing to conditions of its habitation. In shallow tide-pools it is pale and 
