592 MR JOHN RATTRAY ON ECTOCARPUS. 



bare Umwandlung ihres Inhaltes, die sich von der der endstandigen Sphacelen 

 wesentlich unterscheidet, gestattet noch keine sichere Deutung. Entschiedene 

 Parasiten sind mir in ihnen nicht aufgefallen. Es ist mir nicht fraglich, dass 

 es diese Bildungen sind, welche einige altere Algologen als sitzende Sporen 

 beschriebon und abgelildet haben." 



The parasitic or non-parasitic nature of the much swollen club-shaped cells 

 represented in plate ix. fig. 9, d, and in plate x. figs. 5, 6, and 7, the contents of 

 which escape as free swimming ciliated swarmspores, a more or less definitely 

 defined network of the mother cell walls being left behind, this author also 

 leaves undecided, remarking — " Ich habe diese Bildung, die sich, wenn sie 

 nicht in den Entwickelungsgang der Pflanze selbst gehort, an keine bekanntere 

 Parasitenform anschliesst, bisher nur an der Sphacelaria olivacea von Helgoland 

 aufgefunden ; an anderen Sphacelarien ist sie mir nicht aufgestossen. Sie ver- 

 langt eine weitere, eingehende Beriicksichtigung." 



Cohn,*" in 18(37, drew attention to the fact that Chytridial parasitic organisms 

 had often been represented as part of the tissue proper of the host plants, e.g., 

 by Solier and DERBES,t in the case of Aglaophyllum ocellaturn, while Magnus 

 refers the " abnormally swollen up apical cells in Ceramium spiniferum, Kiitz., 

 figured by Cramer, to a new species of Chytridium — Olpidium tume/aciens, 

 Mag., | which is figured by Harvey § as probably the antheridia of Callitham- 

 nioii dispar, Harv.; he also believes that the "abortive spore mother cells," 

 figured by Nageli || in Callxthamnion cruciatum, are referable to the parasitic 

 Chytridium plumulce, Colin. 



Professor E. P. Wright H maintains that Grunow ## has taken parasitic 

 Chytridia for true spores in CaUithamnion, and possibly in Leda capensis (Grun.), 

 &c. 



In Ectocarpus granulosus, Professor Wright " has watched through all its 

 stages, save that of germination, the Chytridial form which has been mistaken 

 for an oosporangium," and while satisfying himself that the parasite is the "only 

 fruit known " in Ectocarpus crinitus, he believes that in E. sphcerophorus the 

 oval cells, although they may not be foreign bodies, are " most suspiciously like 

 some Chytridial growth." 



* F. Cohn, "Beitrage zur Physiologie der Florideen," Max Schultze's Archivfiir Mikroekqpisclie 

 Anatomic, Bd. iii. s. 41, 1867. 



t Capt. Solier and Dr Derbes, Memoire sur la Physiologie des Algues, p. 67, pi. xxi. figs. 10-1 2. 



% Magnus, in Jahrherlrht der Commission zur ■wissenschaftlichen Uniersuchung der deutschen Meere 

 in Keil, fur die Jahre 1872-73, Berlin, 1875. 



§ Harvey's Phycologia Australica, vol. vi. 1862. 



|| Niigeli, Die nenern Algensystem, Zurich, 1847, p. 202, Tab. vi. fig. 1, s, s; 4, s, s. 



U Prof. E. P. Wright "On a Species of Rhizophydium parasitic on Species of Ectocarpus, &c." 7'< 

 Roy. Irish. Acad., vol. xxvi. August 1877. 



* Grunow, Reise S. M. F. Novara um die Erde. Botanik, Th. i. Algen, Tab. vi. 



