567 
XXXIII. Observations y^n the Gonidia and Confervoid Filaments of Mosses, and on the 
relation of their Gonidia to those of Lichens and of certain freshwater Alga. By 
J. Braxton Hioks, M.D. Lond. t F.R.S. and L.S. 
Bead June 5th, 1862. 
FOR a considerable time it has been known that the Thallophytes throw off certain 
b 
le cells, called gonidia, which are capable of reproducing the species ii 
they spring. It has also been known that, to a limited extent, they possess the power 
of segmenting before they produce a new thallus. The observations of a l< \\ Con- 
tinental naturalists* pointed out that they could not be distinguished optically from 
the then-called Protococcus-torms ( Chlorococcus) . 
These observations, however, had attracted but little general at t ention to the matter. In- 
deed their tendency was such that, fully carried out, they necessitated a reconsideration of 
all the Palmellaceas or pseudo-unicellular Algse (Braun) and of the true unicellular AlgsB 
(Braun) . The contemplation of such a revision might well be considered sufficient to alarm 
even the most persevering systematist ; for it involves the very arduous task of watching 
the growths classed under these heads throughout a long period, and under every possible 
change of external conditions, with this additional difficulty, that, in case the observations 
produced no decisive result, they could not be admitted as absolute evidence that these 
forms were really unalterable, because the conditions to which they were thus exposed, 
perhaps, might not include all the combinations of influences to which they were liable 
in their natural state. Besides this, there is the fact already pointed out in the course 
of my observations on the gonidia of Lichens t, which increases the difficulty of 
proving the separate existence of these and allied growths, namely, their continuing in 
the same form of existence for an indefinite period, segmenting continually, till ex- 
ternal conditions are favourable for inducing a change in the mode of growth, in winch, 
again, they may continue for an equally indefinite period, and so on in every phase 
through which they are capable of passing. I believe the task just indicated has not yet 
been continuously undertaken ; and at present any attempt at fixing the true position 
of these organisms would be completely vain and disappointing till more extensive re- 
searches in all directions shall furnish sufficient materials on which to argue^ 
The observations on the development of the gonidia of the Lichens which I have 
brought forward in the • Journal of Microscopical Science,' 1860 (July and October) 
and 1861 (Januarv), also on the growth and diamorphosis of Lyngbya mnrahs, and 
on the statospores % of Voir ox in 1861, show that from these plants large quantities and 
* 
t 
Mey 
Quart 
n 
of Hydro- 
dictyon. Translated in Quart 
VOL. XXIII. 
4 
