90 SEAWEEDS 
CHORDARIACE. 
General Characters—The Chordariacece are a some- 
what ill-defined assemblage of forms, agreeing in the 
possession ofa slimy thallus, varying considerably, 
however, in its outward shape and mode of develop- 
ment, most frequently strand-like, but in some cases 
cushion-shaped and clothed in all cases with filaments 
of which the primary function is assimilative. Both 
plurilocular and unilocular sporangia occur, and these 
also vary in their mode of origin. The unilocular 
sporangia arise either in the place of the assimilative 
filaments or as lateral outgrowths of these, while the 
plurilocular sporangia are produced either in similar 
fashion or by the transformation of a portion of the 
assumilative filaments. 
The Thallus—Though there are gaps in our 
knowledge of the development of a number of the 
genera, it is probable that most of those having a 
strand-like growth more or less resemble Chordaria in 
this respect. It has an axial tissue of parenchymatous 
character, clothed with assimilative filaments and 
hairs. Growth in length is effected by the division 
of the subterminal cells of the thallus, which con- 
tribute to the growth of the axial tissue on the one 
hand and to the production of terminal assimilative 
filaments on the other. These eventually, by the 
production of new ones and the progressive growth 
of the thallus, are pushed aside and take the position 
of lateral filaments. More simple modifications of this 
mode of development occur in the other genera of 
