414 
sons which you have assigned, yet I found myself 
unavoidably compelled to make use of it; as both 
Gmelin and Gertner (but more particularly the 
last) have endeavoured to establish a material diffe- 
rence in the propagation of marine plants. You 
will readily perceive the force of my remark, from 
the following passage in Gertner, p. 19 :—“ quod 
non alia in Ceramiis, quam per solas gemmas locum 
habeat propagationis ratio: dum contra in omni 
genuino Fuco vera reperiantur semina utero car- 
noso, a matris cortice ac medulla distinctissimo, 
conclusa.” 
And yet the same author maintains that these 
very seeds are produced by a simple unassisted 
power :—“ quod in Fucis genuiis....... Ipse 
PERS icy. officia genitalium wtriusgue sexts, 
prestet solus.”—Vide p. 33. 
One of the great points which Geertner endea- 
vours to establish, is, that the less perfect Fuci, 
(1. e. complanatt), as well as the Conferve, have a 
different and more simple mode of propagation than 
the former; and that it is effected only by gemme. 
He makes this distinction between the origin of 
semen and gemma :—“‘Quod gemme medulla sit 
pars zdentica medulla maternee, dum contra semznis 
medulla... .. a matris sue distinctissima.” 
I think I have evidently proved that the grains 
in the Confervz are as much entitled to the appella- 
tion of seeds, as those in the perfect Fuci: nay, more 
so, because the medullary substance of the Conferva 
corallinoides is a liquid, while the grains contained 
in clusters at the joints are solid and opaque. 
