490 LIFE-HISTORIES 
into a new Nemalion plant. Spores which are thus the indirect 
product of fertilization are called carpospores.1 
Sexual reproduction in Chondrus (Fig. 118) as also in almost all 
of the Rhodophycee is by means of carpospores. The process is 
often much more indirect and complicated than in Nemalion; and, 
as is the case with Chondrus, the details may be somewhat modified 
Fie. 320.—Thread-weed (Nemalion multifidum. Thread-weed Family, 
Helminthocladiacee). I, branch bearing male gametangia (sp), and a 
female gametangium with swollen base (c) and slender neck (é). II, a 
female branch after fertilization, the neck (¢) withered, and the base 
beginning to divide for the formation of branches. III—V, later stages 
in the formation of branches which finally bear spores. All much 
magnified. (Thuret and Bornet.)—A brownish-red seaweed with 
branches 5-20 cm. long, on exposed rocks at low-water mark, North 
Atlantic coast. 
by formation of the carpospores within the thallus, as shown in 
Fig. 321. Non-sexual reproduction is accomplished very generally 
throughout the class by non-motile spores, which are produced 
usually four in a sporangium. The sporangia may be either at the 
surface or embedded within the thallus as in Chondrus. 
The thallus in this genus, as with a large part of the class, 
exhibits a differentiation of cells similar to that already 
1 Carp’o-spore < Gr. karpos, fruit. 
