448 Proceedings of the Royal Irish Academy. 



S. pseudosolitarium, n. sp. 14 N. 



This species comes very near to Ectocarpus soUtarius, Sauvag., 

 whicli the founder has more recently discovered to be less 

 solitary than he at first supposed. Sauvageau says of S. pseu- 

 dosoliiarmm, as we propose to call it : — " Levotre a des dimen- 

 sions assez concordants avec le mien, mais vos sporanges sent 

 un pen plus globuleux, les filaments un peu plus longes et les 

 parvis un peu plus epaisses. De plus, tandis que VE. soUtarius 

 a des filaments qui se terminent en poil, je ne crois pas que le 

 votre se termine jamais en poil ? " 



S. Zanardi)iri? (Crn.) 14 IN". 



This species forms minute tufts on the thallus of Chylocladia 

 haliformis. In submitting preparations of it to M. Sauvageau 

 he expressed the view that it was probably the Ectocarpus 

 Zanardinii of the brothers Crouan. Examination of the sterile 

 type specimen is needed for absolute confirmation of this sug- 

 gested agreement. This form was fully worked out with the 

 help of Miss M. C. Knowles. Drawings were made and cases 

 were observed in which the endophytic hyphse passed through 

 the host thallus and formed on the opposite surface new tufts 

 of the parasite. 



Associated with S. Zanardinii {'i), another Streblonema was 

 found which appears to be a new species. Its hyphae and 

 sporangia are larger, and we suggested the name 8. majus for 

 it in a letter to Sauvageau. 



The Irish parasitic Phseophyceje, a difiicult group, are not 

 by any means fully known. 



Ectocarpus, Lyngb. 



Of the 28 species given in the Revised List, only 6 were 

 recorded for Ireland by Holmes and Batters. The genus is 

 well illustrated in Kiitzing's "Tabulae Phycologicse " (V.)- 



E. repens, like. 14 I^. 



This species forms very minute tufts on Cladophora laeti- 

 virens, Harv., on Chcetamorpha aerea Kutz., and on Fucus 

 (Helvick Pt.). 



E. terminalis, Kiitz. 12 N. 14 N. Probably general. 



Forms mere brown covering on the joints of Corallina officina- 

 lis, and on hydroids. 



