44 Mr. Hassall's Notices of British Freshwater Conferva. 



they in this, while in T. stagnicola there is a distinct interval 

 between them equalling that of the diameter of the spores 

 themselves. 



Genus Mougeotia. 



Filaments articulated, simple, at length generally united in 

 pairs, either with or without the intervention of transverse 

 tubes, and either angularly or parallelly. Endochrome at first 

 filling the cells, but subsequently contracting into longitu- 

 dinal or slightly spiral lines. Spores round, situated either 

 in the cells or in the transverse tubes. 

 The genus Mougeotia, as above defined, appears to be a 

 very natural one. The angular conjugation of the filaments 

 is usually regarded as the most important characteristic of the 

 genus. It is not so, however ; for we have angular union of 

 the filaments in an undoubted species of Zygnema, Z. curva- 

 tum. The character of most importance to notice is the cir- 

 cumstance of the cells being at first filled with granular mat- 

 ter, which subsequently generally contracts into longitudinal 

 or slightly spiral lines. 



Mougeotia major. Filaments of more considerable diameter 

 than those of Mougeotia genuflexa ; cells usually five or six 

 times as long as broad ; conjugation angular, and without 

 the intervention of tubes. 

 This species approaches very closely to Mougeotia genuflexa, 



but differs from that species in the much greater diameter of 



the filaments and shortness of the cells. 

 In ponds in brick-fields near Notting Hill. 



Mougeotia glutinosa. Filaments of rather less diameter than 

 those of M. genuflexa, conjugating angularly ; cells six or 

 seven times as long as broad, those being the longest which 

 have conjugated, at first filled with sporaceous matter, which 

 frequently contracts into longitudinal lines : sporidium qua- 

 drangular, lodged between the filaments, which do not enter 

 into its formation ; spores when perfect somewhat oval. 

 This is a very distinct and fine species, occurring abun- 

 dantly in boggy ponds on Hertford Heath. Not unfrequently 

 a number of contiguous parts of cells unite, forming arched 

 loops or links, separated from each other by the square ova- 

 rium, which is the chief characteristic of the species. 



Mougeotia transversalis. Filaments more slender than those 

 of the preceding species, conjugating angularly ; cells about 

 six times as long as broad, united by transverse tubes. 

 This is by no means an uncommon species, although it is 



