122 NATURAL SCIENCE. i FEB., 
fatal. A few other Fungi, such as certain parasites on Zostera, a 
marine flowering plant, have been recorded with some doubt so far 
as their actual growth in sea-water is concerned. 
This parasitism of Fungus on Alga naturally suggests the case of 
the lichens, where, however, both classes of organisms dwell together 
in amity and their relations are symbiotic rather than parasitic. 
Professor Perceval Wright (18) described in 1879, in an admirable 
paper, ‘‘a new species of parasitic green Alge belonging to the genus 
Chlovochytvium of Cohn,’ which he found inhabiting the fronds of 
Schizonema, Polysiphomia, &c. A consideration of this form opens fresh 
ground, since it, like the type form of Chlovochytvium, inhabiting duck 
weed, described by Cohn (19) in an interesting paper on parasitic Alge, 
does not appear to be a case of true parasitism, but rather of that sort 
called by Klebs ‘‘ Raumparasitismus,”’ in which the host furnishes 
merely lodging without board to the intruder. There are many such 
cases among the lower Alga, and their bearing on symbiosis and 
on the parasitic habit itself is an instructive one. A large number of 
Algz (especially marine forms) live as epiphytes on larger Algz, and, 
indeed, constantly select the same species of host and the same part 
of its thallus. Many of these deserve special investigation, since cases 
occur in which the rhizoids of the epiphyte (and even wedges of its 
tissue, like haustoria) penetrate the host, and if not actual burglars are 
certainly in a very compromising position. We have an example of 
more than mere ‘“‘ Raumparasitismus ” (we thank Klebs for that word) 
in Phyllosiphon arisart, a siphoneous Alga which lives in the intercellular 
spaces of the leaf of Avisarum vulgare and even consumes the chlorophyll 
in the adjacent cells. Other Algze are known to inhabit the tissues 
of flowering plants, of Azolla and of Muscinee, but the considera- 
tion of these is at present leading us away from the subject. Ciloro- 
chytrium (which may be put among the Protococcacez) furnishes us at 
any rate with a case of symbiosis, so far as shelter is concerned, 
between Algz, and the line of investigation so successfully pursued 
by Professor Perceval Wright is one that phycologists may be confi- 
dently incited to follow. 
Finally, and of special interest, are certain tubercles on the 
fronds of Florideze described last year by Dr. Schmitz (20) as caused 
by Bacteria. The numerous cases of error in attributing the causes 
of diseases to Bacteria may make one unduly cautious in accepting 
statements of this kind when the possibility of the Bacteria being 
merely post hoc has not been absolutely excluded by the evidence 
of inoculation experiments. Dr. Schmitz, however, is not the man 
to make rash statements, and his research is a very noteworthy one, 
and one, moreover, that suggests other matters of interest in regardto 
Bacteria. 
I am convinced that the subject of the parasites of Algae—as well 
as that of parasitic Algae—is but in its infancy, and in the hope that 
workers may be attracted to a field of research of great difficulty, 
