271 
it will ever be found so excellently preserved us to settle positively its 
true position in classification. Bennett and Murray state that u mycele 
and bodies which may well be oogones are visible in the preparations” 
of Mr. Smith.* 
A remarkable paper on fossil plants by Prof. P. Martin Duncan, has 
been published in the proceedings of the Itoyal Society of Loudon.f 
The title is, “On some Thallophytes parasitic within recent Madre- 
poraria.” In the course of the paper he refers to the work of other 
writers on organisms in corals. The time range of the various par¬ 
asites is very great, as corals from the Lower and Upper Silurian and 
Tertiary formations show their presence. In the latter case even 
the cell wall is preserved. Their vertical range in the ocean extends 
from the surface to a depth of 1,095 fathoms, and they can exist 
under temperatures ranging from 39.7° to that of the surface water. 
The parasitic growths are observed by means of thin transverse and 
longitudinal sections. Age and length of time since the canals Avere 
bored seem to have no influence on them, for they are just as per¬ 
ceptible in Tertiary as in recent corals. The usual appearance of the 
canals is that of long, dark lines, Avith a clear central space. The 
lines may branch, but are of the same size in stem and branch. Swell¬ 
ings are frequent and granular masses often fill spaces in the canals. 
Prof. Duncan proposes for the parasite the name of Achlya penetrans. 
In regard to the fossil forms he says: 
From the results of my examination of Upper Silurian corals and of Lower Silurian 
arenaceous Foraminifera, it is evident that a parasite closely resembling Achlya pene¬ 
trans lived within them during those remote ages. Corresponding in shape with 
the Silurian form of parasite are others which are fossil within the corals of later 
aares. The main differences Ire tween the ancient and modern forms consist in the 
larger caliber of some of the filaments of the first, their long, often unbrancliing 
course, and the frequent development of Conidia -looking bodies within them, and 
the spherical shape of the spores; but it is quite possible that these are not dis¬ 
tinctions which are of specific value. 
The modern coral parasite is evidently the descendant, with slight, or possibly 
no modification, of those which have flourished during successive world-wide 
changes in floras and external conditions. Hence it would, in all probability, have 
had its life cycle made complicated, and a metamorphosis involving vegetative and 
mobile stages has been superadded. It is not an assimilator of putrescent or rotten 
animal matter, but of the nitrogenous and undecomposed organic basis of the coral; 
and in this it resembles the organisms which destroy some living diptera and other 
aerial insecta. Moreover this resemblance in function is possibly caused by continu¬ 
ance of individuality; and if this be true, it adds vastly to the difficulty of placing the, 
parasite in a philosophical scheme of classification (pp. 252-253). 
The lowly organization and the simple structure of many fungi have 
been the possible cause of the continued existence of. many of them 
through long periods of time. We seem scarcely prepared, hotvever, 
to realize that the forms existing as parasites Avitliin corals of Silurian 
" Loc. cit., p. 330. 
t Abstract in No. 171, Vol. xxv, 1876, pp. 17-18; complete in No. 174, Vol. xxv,1876, 
pp. 238-257, pi. 3. 
