160 SETCHELL— PARASITISM AMONG RED ALG^. 



Reinsch. Schmitz and Reinke (cf. Reinke, 1889, p. 28) described 

 Harveyella mirahilis (Reinsch) Schmitz et Reinke (Choreocolax 

 mirabilis Reinsch) with its antheridia and cystocarps, and finally 

 Schmitz, in his " Systematische Uebersicht der bisher bekannten 

 Gattungen der Florideen," enumerated eight distinct genera of para- 

 sitic red algae, viz., Actinococciis Kuetzing, Ricardia Derbes et Solier, 

 Choreocolax and Syringocolax Reinsch, Jancsezvsk'ia Solms, Epi- 

 sporium Moebius, Harveyella Schmitz et Reinke and Choreonema 

 Schmitz. The last genus was created to contain the Melobesia 

 Thurcti Bornet. 



The enumeration of Schmitz, together with the discovery of 

 tetrasporangia, antheridia and cystocarps in Jancsezvskia and in Epi- 

 sporium, the antheridia and cystocarps in Harveyella, the cystocarps 

 and tetrasporangia in C/iorrowcma, and the tetrasporangia in Choreo- 

 colax were convincing as to the existence of real parasites and led to 

 search for more. In 1891, Richards described the cystocarps as well as 

 the tetrasporangia of Choreocolax Polysiphonicc Reinsch. In 1892 

 Batters made known Gonimophyllum Biiffhami with its cystocarps 

 and tetrasporangia. In 1892, Schmitz published a discussion of the 

 tubercular growths on various red algae, with a view to distinguish- 

 ing those which are true parasites from those which are merely 

 warts or galls. In 1893 Heydrich created the genus Pleurostich- 

 idiwn, a Rhodomelaceous genus parasitic on one of the Fucaceae 

 (Fiicodium) in New Zealand. It is dwarf, penetrating and pro- 

 vided with antheridia, cystocarps and tetrasporangia. In the same 

 year, Schmitz published his very memorable paper on Actinococcus. 

 After a full discussion, Schmitz distinguished between 'Actinococcus 

 and the true nemathecia of Phyllophora and enumerated four species 

 of Actinococcus besides two for Colacolcpis and two for Stcrrocolax. 

 He also considered the placing of these genera, deciding upon the 

 Gigartinaceae, the same family to which the hosts belong, rather than 

 the Squamariaceae, where Actinococcus had previously been as- 

 signed by J. G. Agardh. 



The Actinococcus paper of Schmitz provoked considerable dis- 

 cussion. Darbishire (1894) who had been investigating the species 

 of Phyllophora very carefully, held that the so-called Actinococcus 

 species were the true nemathecia of Phyllophora and repeated this in 



