114 SEAWEEDS 



attack of parasitic entophytal Ckytridiacect, and thus 

 present appearances which have been a source of 

 error in their interpretation. 



The Reproductive Organs are both unilocular and 

 plurilocular sporangia, and the different kinds occur 

 as a rule on different plants. They are rarely 

 (as in Batter sia) 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 gemmse, which, so far as is known, are char- 

 acteristic of this and the following order only among 

 Phceophycece, 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, Chcetopteris, Clado- 

 stephus, Halopteris, and Stypocaulon are represented 



