129 



Fam. a^ii. conjugate^.. 



Char. Filaments simple, equal, often conjugating. En- 

 dochrome mostly figured. Si[>OYangm formed geiierallg hy 

 the union of the contents of two cells, either in different or 

 in the same filaments. 



The Confervce, which we now propose to examine, are per- 

 haps the most curious of all their tribe. When viewed to- 

 gether, they form an exceedingly natural group, but one which 

 is defined rather by the enumeration of a number of cha- 

 racters than by one in particular. 



Their filaments when examined with the microscope are 

 seen to be simple and of uniform diameter; they are for the 

 most part unattached, and in their young condition are 

 smooth and unctuous to the touch, and of a deep green colour : 

 they are formed of an assemblage of elongated cells placed 

 end to end, and all of them enclosed and held in union by 

 an investing membrane, common to all, the interior of these 

 cells being occupied, chiefly with endochrome, which is 

 variously disposed, sometimes in the form of s^^ires and stars, 

 at others it completely fills their cavities : mixed up with this 

 endochrome, are observed numerous vesicles ; these being it is 

 presumed the unfertilized zoospores. 



When the filaments have attained a certain age or period 

 of developement, most of the cells are seen to send forth a 

 little conical process, which unites with a similar protrusion 

 from a corresponding cell of a contiguous filament, an un- 

 interrupted passage of communication between the two cells 

 being thus established. 



While this is occurring, the spiral tubes, if the species be 

 a Zygnema, become confused and coalesce in each cell, the con- 

 tents of one passing out through the passage of communication, 

 mingling with those of the other, and both uniting, are at 

 length moulded into a dark body of either an oval or circular 

 form, and enveloped in membranes ; and which Vaucher, 



K 



