210 SEAWEEDS 



The Geographical Distribution of the family is 

 widespread, Chantransia, Nemalion, Helminthora, 

 and Helminthocladia being represented in British 

 seas, while Liagora is confined to tropical and warm 

 regions of the sea, occurring however as far north 

 as the Mediterranean. 



Chcetangiecc. 



The gonimoblast is a convex, or concave, or spread- 

 ing tuft of branched filaments, of which the terminal 

 cells produce carpospores. The main difference 

 between this family and the last is in the fact that 

 the gonimoblast is immersed in the thallus and 

 always enveloped in a special, thick, cellular fruit 

 wall. The gonimoblast originates from one side 

 only of the carpogonium as in Chantransia ; at all 

 events this is the case with Scinaia, in which it has 

 been carefully observed. 



Scinaia has a dichotomously branching thallus, 

 consisting of a central axial tissue, from which there 

 issue at right angles radiating, loose dichotomous 

 filaments, constituting an intermediate tissue between 

 the axial and peripheral tissues, the latter being com- 

 posed of large colourless cells, with small ones filling 

 up the spaces between them. Externally it is 

 gelatinous. The cystocarps occur immediately be- 

 neath this peripheral tissue. Chcetangium has a 

 strong, vigorous, irregularly branched thallus with 

 foliar expansions, often transformed into air-floats. 

 Galaxaura and Actinotrichia have more or less 

 encrusted peripheral tissues with slight annulate 



