cellular structure is exactly that pro|)er to the genus. No conceptacles have 

 been seen. The colour when recent is dull, somewhat livid-purple ; in the 

 herbarium it is a dark reddish-brown. The substance is coriaceous, firm 

 and tough. In drying the fronds do not adhere to paper. 



In its dull-purple colour this species differs from other Th^/- 

 scuiocladics, while in general habit, in tough and rigid substance, 

 and in the cellular structure of the frond, it agrees with all the 

 species. The colour is more like that of many Laurencice, but 

 the substance is far more rigid than in any of that genus. Sonder 

 compares his plant with T. opposiiifolia. If mine be specifically 

 the same, there is not much danger of these species being mis- 

 taken for one another, the much broader frond, the flattened pin- 

 nules, and the colour sufficiently marking the present plant. 



It appears to be a rare species ; and, like all the others, is a 

 deep-water plant. 



"Fig. ]. Thysanocladia laxa, — the natural size. 2. A cross section through 

 the frond, — magnified. 



