16 M. FOSLIE. [1899 



have examined fragments of other algæ in one of the above men- 

 tioned doubtlessly authentic specimens. Here I found Sijliacelaria 

 radicans partly loose between the lower lamels partly one small 

 specimen attached to the species in question. Sph. radicans grows 

 according to Harvey on ,;Sand-covered rocks, between tide marlvs". 

 It scarcety descends to any greater depth. Besides I met with 

 Ceramimn ciliatum, Cladophora sp. (probably Cl. albida Phyc. 

 Brit.) apparentty loose, fragments of Calothrix, and some bleached 

 Protococcus-x-esQvahYmg colonies. Thus it seems as i f the present 

 form occurs both in the lower part of the iitoral region, which 

 accords with the transitions Mr. Hanna and I met with at Round- 

 stone, as well as farther down. It probabty lives in somewhat 

 sheltered places but scarcely in quiet bays which, on the other 

 hand, is the case with Lithophyllum dentatum f, Macallana, a 

 remarkable and large form strange to say not recorded by Harvey, 

 althoLigh apparently coUected in great number by M'Calla. There- 

 fore as above remarked we may be allowed to suppose that some 

 mistake has been committed in Harvey's communications. 



In British Museum's herbarium is a fragmentary specimen of 

 f. aga^iciformis exactly resembling Irish specimens, but it is labelled 

 „West Indies". It is difficuit to know whether this is wrong or 

 not. However, it is recorded in Rep. Challanger Exp. Vol. I, p. 

 113 from Bermudas, Lefroy. 



L. liclienoides is a well known species since long ago, but 

 it has scarcely been considered so varying as is to be seen from 

 the above remarks. I do not here mention more nearly the struc- 

 ture, in which respect it is somewhat varying, though not much, 

 partl}^ and most frequently with rather long central cells but now 

 narrow now broader even in one and the same specimen, and 

 here and there with remarkably short cells. The most characteristic 

 form is in my opinion f. heterophylla, being coarser and commonl^' 

 with a little smaller conceptacles of sporangia than in the allied 

 forms, but not or very slightly varying as to structure. Otherwise 

 the variation in this species is very often due to the shape of the 

 substratum as well as in part local conditions. 



