234 PROCEEDINGS OF SOCIETIES. 
as in Arcyra punicea, he finds rings instead of spirals, and, in 
some threads of the former, rings and spirals at the same time, 
with the addition of bladder-like swellings or beads towards the 
extremities. In Zrichia abietina the spiral branches, and after 
two or three volutions become simple again, then running in a 
horizontal detection so as to form imperfect rings, and then again 
becoming oblique, exactly after the fashion of the mixed vessels 
of Phenogams. Such phases, it is clear, could never be pre- 
sented by any twisting of a flat thread, even where there is one 
spiral alone—not to mention the fact that the threads are, from 
their earliest growth, not flat, but cylindrical—much less where 
the threads themselves are branched and, at the same time, irre- 
gular in outline, as is frequently the case. Tull a thin vertical 
slice from a thread can be obtained, it may be impossible to say, 
so positively as to convince all gainsayers, notwithstanding the 
deeper tint, whether there is really any deposit in the inside of 
the threads corresponding to the spiral markings, though in rx 
case the elevations are due simply to some action within, whic 
take place in a spiral or circular direction, passing occasionally 
from one into the other. 
I have examined Mr. Knight’s specimens, prepared precisely 
according to his directions, and with an object-glass of one-fifth I 
see, clearly enough to satisfy myself, that there is a depression in 
the membrane of the thread between each spiral exactly as the 
structure is figured by Wigand, and, indeed, previously by Mr. 
Currey,* though, at the same time, it seems clear to me that there 
is no twisting of the thread, and that the appearance could never 
have been brought about by mere torsion. In Battarea I have 
seen the vessels more closely approaching the type in Phe- 
nogams; and, unless I am greatly deceived, I have on former 
occasions, in individuals of Trichia which had just passed from the 
milky stage, seen nearer approaches to this than any which are 
figured in Wigand’s plates. Be this, however, asit may, whether 
the difference be greater or less, it is pretty certain that the spiral 
marking of the threads is a case rather of affinity than analogy; 
and we cannot entirely deny the existence of spiral vessels in 
fungi, though they may exhibit a somewhat different type from 
that to which we are accustomed. I have seen precisely the same 
arcuate elevations in the cells of Sphagnum, respecting the spiral 
threads of which I believe there is no doubt.—Jowrnal of Lin. 
Soc., Vol. VII, p. 54. 
On the SPICULA contained in the Woon of the WELWITSCHIA, and 
the CRYSTALS pertaining to them. By Colonel Puitre Yorxe, 
E.R.S. . 
WueEn the spicula were immersed in dilute hydrochloric acid, 
even though they remained in the liquid several hours, there was 
no action on the crystals. 
* © Quart. Journ. Mie. Sci.’ Vol. ITI, Pl. I, fig 4. 
