42 Mr. HassalPs Notices of British Freshwater Confervas, 



of a hollow process between almost every pair of cells in the 

 same filaments ; spores oval. 



I met with sufficient of this species in the vicinity of High 

 Beech to enable me to preserve several specimens of it. 



Genus Tyndaridea. 

 It has been surmised of the two little bodies into which the 

 sporular mass in each of the cells of the species of this genus 

 is invariably divided, that the one consists of fertilizable mat- 

 ter, and the other of that which is to be fertilized ; and this sup- 

 position is in a measure supported by the circumstance of a 

 channel of communication frequently existing between them, 

 but it is opposed by the fact that these little masses are con- 

 tinually undergoing division and separation according to the 

 growth of the filaments ; so that each furnishes the material for 

 two others from time to time, which themselves again undergo 

 division. These sporular masses present a different form in 

 each species, and are thereby doubtless designed to assist man in 

 his endeavours to discover the differences between these minute 

 productions ; they are, in fact, to be regarded as so many 

 seals placed upon them by their Divine Creator, by means of 

 which they may be frequently distinguished from each other. 



Tyndaridea gracilis of Vaucher ? Filaments nearly equal in 

 diameter to those of Tyndaridea stagnicola ; cells four times 

 as long as broad, sometimes five times, at first filled with 

 sporaceous matter as in the species of the genus Mougeotia, 

 which subsequently contracts into two rarely perfectly di- 

 vided roundish masses. 



It is most probable that the above species is the Conjugata 

 gracilis of Vaucher, but this cannot be ascertained with cer- 

 tainty without seeing it in a state of reproduction. The fila- 

 ments may however be readily recognised by the above de- 

 scription. 



Tyndaridea stagnicola. Filaments slender ; cells about two 

 and a half times as long as broad ; sporular masses some- 

 what cruciform ; spores circular, contained within the cells, 

 the diameter of which they entirely fill, as well as a portion 

 of the connecting tube. 



I cannot identify the above species with any described by 

 Vaucher or Agardh. The filaments are more slender than 

 those of Tyndaridea bicornis, but the species is to be distin- 

 guished from all others with which I am acquainted by the 

 circumstance of the seeds passing a little way into the con- 

 necting tubes. 



Abundant on Hertford Heath. 



