166 SETCHELL— PARASITISM AMONG RED ALG^. 



other on a species of Delesseria, as well as a single species of a new 

 genus on Neuroglossum Andersonianum J. Ag. ; and in Rhodo- 

 melacese, two new species of Stromatocarpiis on Ptcrosiphonia 

 Baileyi (Harv.) Falkenb. and on another species of the same genus 

 respectively. These new genera and species are in a fairly advanced 

 stage of preparation towards description and illustration. 



In summarizing the distribution of these distinctive parasitic 

 genera, among the red algae, we find the results as follows : 



Helminthocladiacese i genus with i species. 



Gelidiacese 2 genera with 5 species. 



Gigartinacese 5 genera with 12 species. 



Sphcierococcacese i genus with 2 species. 



Rhodymeniacese 3 genera with 3 species. 



Delesseriacese 2 genera with 4 species. 



Bonnemaisoniaceje i genus with 2? species. 



Rhodomelacese 9 genera with 17 species. 



Ceramiacese 2 genera with 2 species. 



Squamariaceag .1 genus with i species. 



Corallinacese 2 genera with 2 species. 



This summary shows clearly the extent of the distribution of 

 parasitic genera and species through the group of the red algae and 

 the fact that they are, thus far, known only from eleven of the 

 twenty-one families into which the group is usually divided. It also 

 shows that of these eleven families, two, viz., Gigartinacese (with 5 

 genera and 12 species) and Rhodomelacese (with 9 genera and 17 

 species) contain one half or over of the known genera and species. 



Besides the literature dealing with the strictly systematic side 

 and describing, for the most part new species, there are a few papers 

 which attend mostly to other matters connected with the parasitic 

 red algae. Such, for instance, is the paper by Nott (1897) discuss- 

 ing the finding of certain parasitic red algae on the coast of Califor- 

 nia, and a similar paper by the writer published later (cf. Setchell, 

 1905). Sturch (1899) published the results of a careful study into 

 the structure, development, and nature of the parasitism of Har- 

 veyella mirabilis Schmitz and Reinke and its systematic position. In 

 1905, Oltmanns (p. 319 et seq.) discussed parasites among the algae, 



