MICROSCOPY. r 
resemblance of gonidia to algæ does not prove identity, that they 
have microscopically demonstrated the genetic connection of the 
gonidia with the hyphen threads of that lichen, and that Tulasne 
has raised lichens from lichen spores, without the presence of any 
algæ; hence the Berlin Academy has announced the following 
Prize-question: ‘* The proving of Schwendener’s view of the 
double nature of the lichen,” by means of original investigations. 
And they recommend the study of the following points. 
lst. An exact study of the numerous one-celled forms of alge 
which so closely resemble the gonidia of lichens. These are now 
classed in the genera Pleurococcus, Cystococcus, Glococystis, etc. 
2nd. Continuous investigation on the gonidia contained in the 
thallus of lichens, especially with regard to their development 
after being freed from the lichen thallus for the purpose of ascer- 
taining with more certainty the different types of alge that ap- 
pear. The question whether among the great number of green 
gonidia, inhabiting lichens, there may not be more numerous types 
than has been supposed, taken in connection with the investiga- 
tions suggested above on the free living forms of alge ought 
be kept clearly in mind. The case of the occurrence of different 
forms of gonidia in one and the same lichen deserves special 
attention 
. The carrying on of repeated ‘“culture-from-spore” experi- 
ments with lichens from different families with and without the 
presence of the algæ that are supposed to be the nourishing plants. 
This should be especially done with lichens containing chloro- 
phyl-green gonidia. 
The work may be presented in German, Latin, French, English 
or Italian. Important points of investigation must be illustrated 
by tam and the presentation of preparations (microscopic) is _ 
advisa 
The Pee for sending in the papers is fixed at the first of March, 
1875. Real names are to be sent in sealed envelopes. The m 
is one hundred ducats.— T. D. B. 
Misnamine OpsJECTIVES.—[Mr. Wenham has made public the 
following brief reply to Mr. Stodders communication on this 
subject in the August number of the Naturauist. This contro- 
versy, having already called sufficient attention to the points 
at issue, would be fruitless if still farther prolonged.] I should — 
