262 MEMORANDA. 
not fully silicified, of frustules undergoing self-division. 
Actinocyclus triradiatus must therefore be cancelled entirely. 
Mr. Edwards afterwards refers to some remarks on Eupo- 
discus, 11 the ‘ Micr. Transactions,’ vol. vu, p. 19, m a way 
J do not exactly understand; but my intention there was to 
show that the form called Eupodiscus radiatus by Professor 
Smith, was distinct from Professor Bailey’s species of the same 
name, and in fact a Biddulphia. At |that time I had not 
seen Professor Bailey’s species, but having since received 
authentic specimens, my opinion is fully confirmed; Bailey’s 
species is a true Eupodiscus, with projecting processes or 
“feet,” all similar in form, as in FE. argus, and quite 
distinct in structure from the form which occurs in the 
Thames, and elsewhere on our coasts. The processes are 
merely hyaline projections, without any markings, and there 
are no spines. I consider, therefore, that Eupodiscus radiatus, 
Smith, should be cancelled, and Biddulphia radiata be sub- 
stituted for our English species; whilst Hupodiscus radiatus of 
Bailey may be considered as a good species, known, however, 
at present, only in America.—F. C. 8. Rorrr. 
