114 SEAWEEDS 
attack of parasitic entophytal Chytridiacee, and thus 
present appearances which have been a source of 
error in their interpretation. 
The Reproductive Organs are both unilocular and 
plurilocnlar sporangia, and the different kinds occur 
as a rule on different plants. They are rarely 
(as in Battersia) differentiated terminal cells of the 
axis or ordinary branches, but generally the terminal 
cells of special branches (their stalks, in fact), which 
arise sometimes singly, sometimes in tufts, in a con- 
siderable variety of relations to the axis and 
branches in the different genera. The unilocular 
sporangia are mostly round or oval in form, the 
plurilocular cylindrical or obovate. The latter in 
some instances may be branched at the base. 
The gemme, which, so far as is known, are char- 
acteristic of this and the following order only among 
Pheophycee, are short branches, which cease to grow 
in length and send out two or three lateral short 
processes at the top, while the apical cell which had 
ceased to grow in length,.emits a hair. The basal 
cell remains undivided and the gemma breaks off 
above it. On being set free, the terminal cells of 
the short processes or of the stalk grow out into a 
creeping filament, which bears new shoots as lateral 
branches. 
The Geographical Distribution is a general one, but 
possesses most representatives in north and south 
temperate seas, especially on the coasts of the North 
Atlantic and the Australian region. Battersia 
(peculiar to Britain), Sphacelaria, Chetopteris, Clado- 
stephus, Halopteris, and Stypocaulon are represented 
