78 



The Naturalist. 



As mentioned in my short note lately (Aug. N., p. 24), diatoms were 

 very few as to species found, and those but common ones, though I 

 think -S". spicula is a new record. 



The Alg^ are such as one would expect to find in such a habitat, 

 though several common species and genera were not seen, but 

 they probably exist. 



As might be anticipated, fresh-water rhizopods were plentiful, with 

 some of the smaller entoniostraca, &c. ; among these I may mention 

 en passant, Arcella vulgaris, Bifflugia proteiformis, Actinoplirys sol, 

 Traclielocerca viridis, Kerona mytilus, Cantliocamptus mimitus, and Amosb(S. 

 The pretty Infusorian Binohryon sertidaria was abundant. 



It may be as well to mention that the drawings of DesmidiesQ are 

 usually made (by common consensus of opinion) to a uniform scale of 

 400 diameters, and this is a good rule in papers wHich relate to the 

 controversial side of botany ; but on the present occasion I have 

 thought well to violate it in order to show more of the strange forms 

 which desmids present. On another point — that of measurement — I 

 quote Mr. Wills (Midland Nat. 1881, p. 41). " The unit -01 m.m., 

 is recognised by continental botanists under the symbol and the 

 dimensions of the Desmidieag are recorded in the following manner : — 

 ^ e.g. Long. = 21 /i ; Lat. = 20-21 \i ; Lat. isthmi = 5 /x.' It is only in 

 this country that the barbarous notation of inches and their decimal 

 parts still lingers." These remarks now apply to all micro-metric work. 

 I trust the reference to this will be excused, for though a smaU matter 

 of detail, it is yet important, and saves much comparison and calculation. 



In the accompanying list there are many forms in the genus 

 Cosmarium, and several in that of Closterium, as yet undetermined. 

 I think, moreover, that the Staurastra will repay further search. 



For the filamentous algae and diatoms I have not given all the 

 " authorities," deeming such as are given to be sufficient for the Union 

 lists, and some I have not at this moment. 



Fosur specimens have a query against them. Of three I feel tolerably 

 sure, having drawn them under the microscope ; of the fourth {S. Prings- 

 Jteimii) my drawing is not quite satisfactory, though very near the form. 



Finally, I must roundly state my opinion that in the various descrip- 

 tions of new species by many authors, too many varieties have been 

 exalted into species. To anyone curious on this point I refer Dr. M. C. 

 Cooke's remarks on the forms of Tetrachastrum in " GreviUea " for 

 March, 1881. 



The specimens marked with an asterisk are, I think, new to 

 England ; though either Mr. Archer, of Dublin, has found them in 



