obferving, what I truft I may be allowed to obferve without fear of being con- 

 fidered guilty of detraction, that almoft all the plates of Confervas in the 

 Catale&a Botanica are copied from plants, either in a dry ftate, or which have 

 been dried. They are not therefore in general applicable to the fpecies examined 

 while recent. Many of the defcriptions labor under a fimilar difadvantage, from 

 the learned author's refiding at fo great a diftance from the fea. It was necef- 

 fary to mention this circumftance on my own account ; becaufe, had it not been 

 noticed, it muft have been thought that the figures in this work contradict thofe 

 of Dr. Roth, and, {till more, becaufe nothing would be more likely to miflead a 

 young botanift. The fructification of C. diffufa has not yet been difcovered ; it 

 adheres, when dried, very (lightly to paper, and not at all to glafs. 



A. C. diffufa, natural fize. 



B. Ditto, magnified 4. 



C. Ditto, 2. 



