442 Proceedings of the Royal Irish Academy. 



have found invagination of sporangia so general that no classificatory 

 importance can be attached to its occurrence. It is highly desirable 

 that the Fauna and Flora Committee should be encouraged to devote 

 attention to this branch of investigation, so important from both a 

 purely biological and an economic point of view. ^ 



Speaking of the Phseophyeae, Janczewski ^ says : — The Phaeo- 

 sporeae constitute " un groupe de families nettement caracterisees ; le 

 nombre des representants de chaque famille est quelquefois reduit au 

 minimum possible, a une seule espece ce qui indiquerait I'existence 

 tres ancienne de cette classe dont les representants auraient ete con- 

 serves jusqu'a I'epoque actuelle en petit nombre seulement." 



Sauvageau suggests that the above supposition may account for 

 the great differences of behaviour exhibited by the reproductive 

 bodies. 



From an economic point of view the group is of considerable 

 interest. 



The Laminariaceae, or oar- weeds, are the source of kelp — an im- 

 portant industry to many on the west and north-west coasts of 

 Ireland. It is unfortunate that the term " red-weed" is so generally 

 used to indicate the kind used in kelp-burning, as the true red sea- 

 weeds (Floridese) are not generally, and should not be at all, used. 

 The term "red-weed" indicates a primitive appreciation of colour 

 distinction. 



Rubber fistules seem to be displacing the Laminaria stalk fistules. 

 for surgical purposes. 



The Fucaceae, or black-wracks, contain a small percentage of 

 iodine, and are an adulteration in kelp-making ; they are mainly 

 used as manure. In Norway, Dr. Foslie tells us, that the black- wracks 

 are banked for some three or four months in alternating layers of 

 ordinary soil, or road-scrapings and seaweed, a foot thick, thus making 

 a much more excellent manure than is obtained by the use of the fresh 



iThe appearance in 1892 of Sauvageau's article, " Sur quelques Algues Pheo- 

 sporees parasites," marked a distinct advance in our knowledge of the Phseophyceae. 

 We have met with many cases fully confirming Sauvageau's observations. M. 

 Bornet's discovery of the biological significance of the shell-boring Algae has been 

 fully iUustruted in Irish waters. No^ one has yet discovered a member of the 

 Phseophyceae with a shell-perforating habit. 



2 Ed. J. Janczewski. "Observations sur I'accroissement du thalle des Pheo- 

 sporees," p. 116. (Mem. de la soc. nat. des sciences natnrelles de Cherbourg, 

 t. six., 1875). 



