GO 



Veit Bkecher Wittrock. 



branched so as to look like claws or hands in two or more branches (pi. 5, figs. 4, 

 5, 6, 7 It), with which they grasp smaller objects of an organic origin, especially 

 particles of humus and such like things. Sometimes helicoids, ordinarily unbran- 

 ched, are developed from cells that are not terminal; these helicoids can now 

 have the same position as the normal (pi. 5, tig. 1 h) and now as the acces- 

 sorial branches (pi. 5, tig. 3 h). — The spores are partly terminal and partly 

 inclosed, and are found in the principal filament as well as in branches of all 

 degrees. The terminal spores are as a rule elongated and cask-shaped with a 

 tapering and somewhat rounded top (pi. 2, fig. 13; pi. 4, figs. 13 and 16). As 

 exceptions top spores are found of a somewhat anomalous shape, such as pi. 

 2, fig. 13 st and pi. 5, fig. 8 show. (As I have indicated in the paragraph 

 treating the formation of spores, this anomalous top spore has without doubt been 

 intended, from the beginning, for a helicoid). The inclosed spores can have two 

 shapes. They are either swollen and cask-shaped (pi. 5, fig. 2 and pi. 2, fig. 13) 

 or, though much more seldom, cylindrical (pi. 5, fig. 2 sc and pi. 2, fig. 13 at). 

 Connecting forms between both are rare. Inclosed spores of an irregular shape 

 are found now and then. The anomalous shape most frequently has its cause in 

 the circumstance, that the mother cell of the spore had begun, before the formation 

 of the spore, to form a branch, but which was not completed; and from this cause 

 the unfinished branchlet has come to belong to the spore, when it was afterwards 

 formed, making something like a beak pointing upwards from the spore (pi. 2, 

 fig. 14 sr, fig. 15 st). A peculiarity in this species is, in specimens with no rhizo'id 

 or a rudimentary one, that the thallus is rather often ended downwards in a spore, 

 which does then take the place of a rhizo'id (pi. 2, fig. 13 sgb; pi. 4, figs. 12 and 

 14 sgb). The cause of this is, that the spore which has, by its germination, been 

 the origin of the whole individual, has resumed its character of a spore when the 

 germination was completed, by being tilled from above with a protoplasm rich in 

 chlorophyll, and by the formation of a new transversal cell wall above. (See more 

 in exteuso in the paragraph on the formation of spores.) Twin spores are not rare 

 in this species. Most frequently they occur in the top of short branches of the list 

 and 2:d (or 3:rd) degree, but now and then they are also found in the principal 

 filament and in other places (pi. 2, figs. 14 and 15). The lower twin spore is gene- 

 rally smaller, but sometimes it happens that they are of about equal size (pi. 2, 

 fig. 14). In a couple of cases I have observed in this species triple spores 

 (pi. 2, fig. 15 s l , s 2 , s 3 ), formed in the manner indicated in the paragraph treating 

 the formation of spores. Besides the spores formed in a normal manner (i. e. after 

 a preceding passing upwards of the chlorophylliferous protoplasm, by bipartition), 

 there occur in this species cells of the usual form, which contain, like the spores, 

 an abundant quantity of chlorophyll (pi. 4, fig. 18 p). Probably they have the same 

 purpose as the prolific cells mentioned before in P. hewensis nob. 



KhizoTd part of the thallus. In the germination of the spore a transversal 

 wall, vertical against the longitudinal axis of the spore, is formed in its midst or 

 in its lower part. The part situated below this oblique wall constitutes its rhizo'id 

 part. This part consists, as a rule, of one cell. Only in one case, the one represented 

 pi. 4, fig. 18, 1 have found, in P. Cleveana nob., a rhizo'id formed by more than 

 one cell. As the figure here quoted shows, the rhizo'id here consists of three cells, 



