Fertilization of the Floridee. 27 
It is, however, a very common phenomenon that the deve- 
loping auxiliary cell first of all puts forth a rather large diver- 
ticulum, and then separates it off as an independent cell. 
From this cell, as the central cell of the entire fruit-body, 
numerous side-branches then sprout forth, which ramify more 
or less, and finally produce, from single or numerous cells of 
their whole system of ramifications, individual naked carpo- 
spores. The mother-cell of this central cell, the former 
auxiliary cell, however, sometimes remains undivided, some- 
times develops only a few side-branches, which spread out 
laterally and attach the developing spore-fruit to the branch 
of the thallus (Callithamnion corymbosum, Lyngb. &e.), and 
sometimes branches more abundantly, and forms with its 
Callithamnion versicolor, Draparnauld (according to Bornet, ‘ Etudes phy- 
cologiques,’ p. 70, note 4, identical with C. seirospermum, Harv. [ =Sei- 
rospora Griffithsiana, Harv.|, C. stipitatum, Nig., and C. hormocarpum, 
Holmes), forms a loosely branched tuft of filaments, exactly like the 
tufts of Seirospora, which in this species originate by metamorphosis of 
the apices of the branches. These “seirosporiform favelle,” according 
to Falkenberg (‘‘ Meeresalgen des Golfes von Neapel,” in Mitth. der Zool. 
Station zu Neapel, i. p. 255), originate by parthenogenetic development 
of the auxiliary cells, the carpogonia being either early aborted or not 
developed at all, while the auxiliary cells belonging to them continue their 
development notwithstanding. From my own observation, however, I 
cannot agree with this interpretation of the facts. Certainly in C. verst- 
color, Drap. (as in many other Floridez), there are often aborted carpo- 
gonia, the auxiliary cells belonging to which persist. But these auxili- 
ary cells do not grow into parthenogenetic spore-fruits, but simply become 
small sterile thallus-cells in the same way as in other species of Calli- 
thamnion; and these “ seirosporiform favellz” originate from auxiliary 
cells, the carpogonial branch belonging to which develops a normal car- 
pogonium with a well-developed trichogyne. Evidently such carpo- 
gonia were accidentally no longer persistent in the specimens of the plant 
investigated by Falkenberg. 
Moreover Falkenberg ((oc. cit.) cites the present plant not as C. vers?- 
color, Drap., but as C. corymbosum, J. Ag., var. ? sevrosporum, and Ber- 
thold (“ theirs der Algen im Golf von Neapel,’ in Mitth. d. Zool. 
Stat. iii. p. 515) has quite recently united the same plant with C. corym- 
bosum, Lyngby (J. Ag. Sp. Alg. iii. p. 40). From this latter species, cer- 
tainly very similar in habit, in which seirospore are entirely wanting (and 
which, moreover, occurs with C. versicolor in the Bay of Naples), C. ver- 
sicolur, Drap., is distinguished not only by the form of the cystocarps and 
antheridia (to which attention has already been called by Bornet, /oc. cit.), 
but also by the structure of the individual thallus-cells. In C. versicolor, 
Drap., the sterile thallus-cells are always uninucleate, while in C. corym- 
bosum, Lyngby (with the exception of the youngest cells) they are always 
multinucleate (see my statements in the Sitzungsb. d. niederrh. Ges. f. 
Nat.- u. Heilk. zu Bonn, June 7, 1880, p. 125 [p. 4 of the separate im- 
pressions ]). baer «Stet 
So far as I know, a parthenogenetic, ¢. e, apogamic, origin of the spore- 
fruits has never been described in any other Floridee. 
