58 
NEW OR CRITICAL BRITISH ALGM. 
Bognor and now preserved in the Herbarium of the British 
Museum, I was surprised to find them thickly covered with the 
curious bodies a sketch of which is given below: — 
So closely did these bodies resemble Olpidia that had not 
they been filled with 
a grumous green 
matter, I should un- 
hesitatingly have re- 
ferred them to that 
genus. On the ap- 
pearance of Mr. Buff- 
ham’s paper I was 
struck by the close 
resemblance these 
bodies bore to figure 
10 of his Plate. I 
also found that they 
agreed very well with 
the measurements 
given by him. I 
consequently re-ex- 
amined a number of 
specimens, with the 
result that in one or 
two of them I dis- 
tinctly saw the two 
Empty perigloea of Orthoneis binotata, Grunow, x 300. diatoms as figured 
by Mr. Buffham. I am, therefore, forced to the conclusion that 
these Olpidium-like bodies are nothing more than the empty 
perigloea of Orthoneis binotata, and I have little doubt that they 
have often been mistaken for true Olpidia. 
LICHENS. 
Wainio on Lichens. 
( Continued from p. 32.) 
Pseudostroma of Lichens . — The genera Glyphis (Ach.), 
Chiodecton (Ach.), and Trypethelium (Spreng.), established by old 
authors on account of the stroma-like appearance of the excipulum, 
are not kept up by Wainio as autonomous genera for the following 
reasons: — Their anomalous stroma, called by Wainio a pseudo- 
stroma, results from the adherence of the perithecia of agglomerated 
apothecia protruding from the thallus, as in Glyphis , Leptor aphis, 
sub-gen. Tomasiella (Mass.), Arthopyrenia, etc. In other instances 
the pseudostroma is formed from a combination of the perithecia 
(excipulum proper) and the amphithecia (thalloid excipulum). 
Their appearance in general depends simply on the coincidence of 
the prominence and the simultaneous adherence of the apothecia. 
