64 SEAWEEDS 
a hkeness to the tetraspores of the same group. 
Many authors, in fact, describe unhesitatingly both 
these bodies by the terms appropriate to Floridce. 
The contention rests on no more than this slender 
support and the suggestive influence of the employ- 
ment of such terms as tetraspores, &c., for the Ductyo- 
tacew. Theabsence of any observation of fertilisation 
leaves the field open for such speculation. On the 
other hand, no trichogyne has been observed, and 
the presumptive female reproductive organs sug- 
gest degeneration from Phwophycee very much 
more than affinity with Floridew. The antheridia, 
apart from the motionless character of the anthe- 
rozoids, correspond better with similar bodies 
among the Phawophycem, and the envelope en- 
closing the sorus in Dietyota, while morphologically 
not directly comparable with a conceptacle, yet 
resembles it as much as it does any corresponding 
body in the Floridew. The fancied resemblance to 
tetraspores attributed to the non-sexual spores is 
based merely on their number, though this is incon- 
stant (as it is, however, among the Mloridew). But 
the spores are extruded without a membrane and 
their condition is, to say the least, just as consistent 
with loss of cilia as with loss of membrane—a purely 
physiological condition scarcely admissible in such 
an argument. The vegetative organs are over- 
whelmingly in favour of their character as Phwophycee. 
If we take the Cutlertacew,in which the mode of 
thallus development is different, as has been de- 
scribed, we see all three sorts of reproductive bodies 
ciliated, while in Dictyotacece all three are motionless. 
