NOTES AND MEMORANDA. 97 



24 genera, of Avliich 4 are new; of fungi are described 15 

 new species, distributed in 13 genera, of which 8 are new. 



Amongst the most interesting of these new forms of algae 

 are some belonging to each of the three great groups above 

 mentioned, which are of a truly parasitic, that is, entophytic, 

 habit, that is to say, they carry on their existence embedded, at 

 least partially, within the tissues of larger forms. It is only 

 a comparatively short time since algte of this nature were 

 recognised, and a resume of the knowledge of them at the 

 time was given in the ' Quart. Journal of Micr. Science,' n. s., 

 vol. xiii, p. 365, 1873. To the small number already known 

 Professor Reinsch has, in the present work, added consider- 

 ably, and what would seem somewhat surprising is that their 

 distribution would appear to be pretty wide, though the 

 forms are, perhaps, difficult of detection. 



Entonema (n. g., Reinsch), belonging to Melanophyceae, 

 embraces species inhabiting the tissues of both Rhodophycete 

 and Melanophyceae of larger and of lax structure, both super- 

 ficially and in the internal parenchymeof the infected plant; 

 sometimes occupying the intercellular spaces, sometimes 

 penetrating into the interior of the cells. The parasite itself 

 forms jointed filaments with fructification of Ectocarpese. 

 Species referable toEctocarpus itself are described as having 

 rhizomatoid radicles penetrating into the living substratum. 

 Entonema intestinum (Reinsch) produces zoosporangia, the 

 zoospores standing in transverse series. 



Actinema(n. g. Reinsch) is a new epiphytic Melanophyceous 

 genus — its fructification unknown ; the minute plant forms a 

 disc of parenchymatously conjoined cells, to some extent com- 

 parable to Phyllactidium (Kutz.),or Coleochaete (Breb.), minus 

 bristles, flatly adhering to the surface of larger algee. 



In Plectoderma (n. g. Reinsch), referable to Rhodophycese, 

 of which the fructification is also unknown, we have a struc- 

 ture morphologically quite comparable, and apparently of 

 wide distribution. 



Again, amongst Rhodophycese we have a new truly parasitic 

 genus in Choreocolax (n. g., Reinsch,) described Avith several 

 species. The frond is composed of two parts or portions — 

 one an irregularly filamentous system, becoming expanded 

 in the parenchyme of the infected plant ; the other rising 

 above its surface, and forming externally a convex or hemi- 

 spherical, or nearly spherical, or irregularly-lobed cellular 

 body ; the cells of the immersed portion are more slender 

 than those of the external outgrowth, or equal to them ; 

 those of the external part are variously figured, disposed 

 more or less without order, or in subramose densely intricate 



VOt. XVI, NEW SER. G 



