76 Veit Brecher Wittrock. 



Figs. 18 to 20. P. Roettleri (Roth) nob. 

 Fig. 18. Tine lower half of a fertile specimen, without any normal rhizoïd, but 

 •with a lateral branch from the mother spore of the plant. A l)ranch carries a 

 helicoid, /;. 

 » 19. A piece of a branch of the l:st degree with au inclosed pair of twin 



spores a' s". 

 » 20. The top of a branch of the l:st degree with a terminal pair of twin spores. 



PLATE II. 



The figures are magnified 20 times, with the exception of figs. 

 10 to 12, which are magnified 50 times. 



Figs. 1 to 12. Pithophora kewensis nob. 

 Fig. 1. An almost complete specimen with a rhizoïd consisting of one cell and a 

 fertile cauloïd with long branches. 



» 2. Two connected prolific cells, 2' ^^^^ l'\ ^vhich have developed a specimen 

 each. Of the oue developed from p only the lower part is visible. Of the 

 one developed from p the whole is visible. 



» 3. Two connected prolific cells, p and ^j, which have developed one specimen 

 each laterally. The one developed from p is richly ramified, but the one from 

 p is unbranched. The prolific cell p has also developed, apically, a cell 

 which has afterwards formed a spore, st, in its top. 



» 4. The middle part of a fertile cauloïd with numerous but scautily developed 

 branches. 



» 5. Complete specimen with a rhizoïd of one cell, rli, and an almost unbranched, 

 fertile cauloïd. The specimen very plainly shows the basijietal direction, in 

 which the formation of spores regularly takes place. 



» 6. Complete specimen with a rhizoïd of oue cell, rh, and a cauloïd of which 

 the lower part is sterile aud the upper fertile. 



» 7. Complete specimen with an unusually long rhizoïd of one cell, rli, and a 

 cauloïd of which the lower part is fertile and the upper sterile. The lowest 

 subsporal cell of the cauloïd has sent forth a subsporal branch, hs. The spe- 

 cimen has been broken off at X. From the uppermost cell left, the abnor- 

 mall}' short topcell, d, of the principal filament has afterwards been developed. 

 (This specimen and the one represented fig. 6 belong to the so-called half- 

 fertile-half-sterile). 



» 6. Uppermost part of the principal filament in a sterile specimen. The cell- 

 contents are not represented. 



» 9. A piece of a sterile specimen, with an accessorial basal (rhizine) branch, 

 ac, in the act of being formed. 



» 10. A piece of a sterile specimen, of which the cells have partly been attacked 

 by parasitical protozoa. The protoplasm in the middle of the cell of the prin- 

 cipal filament is consumed by the parasites, but the protoplasm left in each of 

 the two ends of the cell has individualized itself to an indepedent cell, after 

 having limited itself towards the spaûe occupied by the parasites by a new- 

 transversal cell-wall. The protoplasm in the uppermost part of the branch-cell 

 has proceeded in the same manner. 



