I 



217 



ADDENDA. 



The following species liave unfortunately been 

 omitted from their proper places : — 



Saprolegnia elongata, Mass. (n. sp.), (figs. 47 — 49). 

 Dioeceous ; a sexual form very much elongated when 

 fuHy developed, main stem slender, 3-4 /j, thick, often 

 flexuous, first zoosporangium terminal, elliptical, 50- 

 60 X 18-21 fi, filled with zoospores which escape from an 

 opening at the apex ; wlien the zoospores have escaped 

 from the first zoosporangium the transverse septum at 

 its base develops into a second zoosporangium which 

 is elevated on a stem out of the first zoosporangium, 

 in this way numerous superposed sporangia are 

 produced ; sometimes two new zoosporangia originate 

 from the base of an old zoosporangium, thus producing 

 a lateral branch ; sexual form with the stem un 

 branched or with very short lateral branches termi- 

 nated by oogonia that are globose, imperforate, 45-60 

 /J. diameter, oospheres 3 — 4; antheridia elliptic-oblong, 

 30 X 10 ^, supported on slender, flexuous branches, 3 — 

 4 of which originate from near the apex of the main 

 stem, which with that supporting the oogonia are 

 about lOyLt in diameter. 



On decaying trunk of tree-fern in a tank. Rare. 



The above species, which has occurred for two years 

 in succession at Kew, I do not find to agree with any 



