45 



what approach thofe of the following fpecies before they afTume their oval 

 form. The general appearance of the two plants is however entirely dif- 

 fimi'ar, but Dr. Roth's account of the wonderful changes which he has 

 obferved in his C. atmulhia, almoft induce me to fufpe£t that they may 

 poffibly both belong to the fame fpecies. For the lower of the two (ketches 

 in Tab. B, I am indebted to my friend Mr. Woods, and they are both 

 made with the higheft power of a compound microfcope. 



25. nummuloidcs. C. filis fimplicibus, tenuibus, fragilibus, fufco aureis ; arti- 

 culis diametro fub-brevioribus, demum in glomerules fub-ovales, monili- 

 formes, approximates mutatis. T. B. 



Among the leaves of water plants in the River Lea at Walthamftow. 



In March, 1802, I found a few detached filaments of the prefent plant, 

 mixed with thofe of C. llneata, among the Trerriella-Iike Dime with which, 

 as before mentioned, many of the plants in the River Lea are covered. 

 I have not difcovered any filaments which appear to be at all perfect, but 

 they feem fufEciently fo to prove that the plant differs materially from 

 every other Britifh fpecies, and by publifhing this imperfect account I truft 

 that I fhall induce fome other Botanift to fearch for it, and more com- 

 pletely afcertain its nature. The filaments are cylindrical, of a brittle 

 nature, and reddifb, yellowifh, or yellowifh brown color. The internal 

 veficles which conftitute the joints appear to be at firft cylindrical, but at 

 length collapfe into an oval form, fo as to give the filaments when highly 

 magnified, fome refemblance to a feries of guineas. The length of their 

 joints is generally fomewhat lefs than their diameter. C. tiummttl r ides, 

 although fpecifically diftlnft, appears to pofTefs fome affinity with a fpecies 

 figured in the 4th Vol. of the Stockholm TranfacKons, under the name of 

 C. moniliformis. The drawing in the fupplementary plate B, reprefents the 

 filaments when magnified with power 1 . 



26. punflalis. C. filis fimplicibus, tenuiflimis, longis, viridefcentibus ; articulis 

 diametro fub-duplo longioribus, fucco in gLbulum folitarium demum con- 

 gefto. T. 51. 



