CATALOGUE OF PLANTS. 415 



S. exoavatum, Ralfs. 



Same habitat. 

 S. vertebratum (Breb.), Ralfs. 



Same habitat. 

 S. serratum, Bail. 



Same habitat. 

 S. Wallachii,(?) Jacobsen. 



Burlington : Brown's Mills. 

 S. rectangulare, Wolle. 



Same locality as the last.* 

 S. moniliforme, Lund. 



Occasional in ponds. 



MBSOT^ENIUM, Naeg. 

 M. micrococcum, Kutz. 



On moist earth. 

 M. Endlicherianum, Naeg. 



In ponds. 



SPIROT^ENIA, Breb. 

 S. condensata, Breb. 



In meadow pools, etc. 



S. obscura. Ralfs. 



In ponds ; rather rare. 



PBNIUM, Breb. 

 P. Digitus (Ehrb.), Breb. 

 P. margaritaceum, Breb. 

 P. interruptum, Breb. 

 P. closterioides, Ralfs. 

 P. truncatum, Ralfs. 

 P. polymorphum, Perty. 

 P. Brebissonii (Menegh.), Ralfs. 

 P. Navicula, Breb. 



All these species frequent in ponds. 



S. secedens of the Preliminary Catalogue is to be omitted. 



