SYNOPSIS OF GENERA 189 
Sexual reproduction through conjugation of gametes similar in 
character, though sometimes differing in size. 
~ Synopsis of Tribes and Genera 
Tribe I. CHAETOPHOREAE 
Plants attached at the base, erect, extensively branched, with more or less differentiation 
of supporting and reproductive portions (except in Microthamnion). All fresh- 
water plants. 
Plants less than 1 mm. high, not setiferous. 7. MICROTHAMNION. 
Plants larger, branches generally pointed or setiferous. 
Filaments fine, showing little difference in character of stem and branches. 
II. MYxoNEMA. 
nearshore 
Fil ts and main 1 hes larger, bearing d an فا‎ 
IV. Se 
Filaments fine, in tufts involved in dense gelatinous substance: 
III. C 
£ 
Tribe II. HERPOSTEIREAE 
Plants سسب‎ S creeping on or within other algae or animals, without distinction 
tween basal and apical cells, and without differentiation of supporting a 
eproductive portions. 
Inhabiting salt water. 
Plants tending to form an expanded thallus, growing on the surface of bryozoa. 
V. BE A. 
Plants simply branched, endophytic within the membrane of Zlachista. 
VI. ENDODERMA. 
Plants bearing special setiferous cells, epiphytic on s Paso ceae 
. BOLBOCOLEON. 
N fresh wa 
Een ‘of flask-shaped cells, bearing setae pine at the base. 
VII HAETOSPHAERIDIUM. 
Plants composed of globose or cylindrical cells, بای‎ setae bulbous at the 
IX. وت‎ 
The genera of the Chaetophoreae are rather closely related, 
though Microthamnion and Myxonema, which are placed together, 
probably had a separate origin. The latter might be naturally 
derived from Ulothrix, while the former may have developed from 
a small Stichococcus-like ancestor. Chaetophora and Draparnal- 
dia may easily be conceived of as developing from Myxonema. 
The genera of the Herposteireae are a somewhat heterogeneous 
group, and perhaps have originated in different ways from proto- 
coccoid ancestors. Only Zpicladia and Endoderma are closely 
related morphologically. Herpostetron seems to approach most 
nearly to the Coleochaetaceae, for it is not a great step from the 
