RECENT LITERATURE ON MARINE ALG^. 231 



receptacles ; M. Gorunncr, recorded on Laminaria pallida at Corunna, 

 and on L. flexicaulis at Croisic ; and M. papillosum on L. saccharlna 

 collected at Croisic and St. Vaast-la-Hougue. The name of this 

 last species is peculiarly apt, since the upright filaments have a 

 very papillose appearance as the result of abortive outgrowths 

 which form lateral protuberances. 



M. Sauvageau deals with Ulonema rhizophorum Foslie, and 

 points out the strong resemblance between it and Mijrionema 

 vulgar e, but for the present at least he maintains it as an indepen- 

 dent species, while waiting for further opportunity of investigating 

 the plant. The morphology of Myrionema vulgare is exhaustively 

 dealt with by M. Sauvageau and accompanied, as indeed are all 

 the species dealt with in this paper, by illustrations of the various 

 points touched on. He deals at length with the growth of the 

 basal portion, showing that in young plants the whole under 

 surface adheres to the substratum while, as the plant grows the 

 centre becomes detached, and rhizoids are formed to hold it fast. 

 Instances are given of the power of the plant to repair injury from 

 outside and an interesting section deals with the secretive apparatus 

 of Myrionema which has never till now been noted. 



M. Sauvageau has also new facts to show with regard to that 

 most interesting growth in the FhaopliycecB, viz. the hairs. He 

 finds that in Myriojiema, as well as in certain species of other 

 genera, the hairs have an endogenous growth, shooting up inside a 

 short filament of cells, which persists to form a sheath round the 

 base of the mature hair. The fact of the growing portion of these 

 hairs being situated near their base would lead us to infer that 

 their importance to the plant has caused this protection of the 

 growing portion. Theories on the function of the hairs are not 

 wanting, and that one which receives most support, and towards 

 which M. Sauvageau himself leans, is that the thin walls and large 

 surface area increase the power of the plant to absorb salts and 

 gases from the sea-water. This fact of the differentiation of hair 

 and sheath is, in M. Sauvageau's opinion, of sufficient importance 

 to become a possible assistance in determining the affinities of the 

 Ph(Eospore(B. 



As regards the reproductive organs of Myrionema vulgare Thur. 

 the author finds that besides the unilocular sporangia there are 

 two kinds of plurilocular sporangia which he calls mega- and 

 micro-sporangia, considering them the homologues of those of 

 Ectocarpiis virescens. He discusses them at length, and describes 

 also the germination of the spores, which, he says, do not fuse. 

 The examination of M. vulgare concludes with an interesting section 

 on the power of the plant to resist death after the breaking up of 

 its host plant, the result of experiments carried out by M. Sauvageau 

 under artificial conditions. It is to be hoped that he may fulfil his 

 intention of carrying out further experiments of a like nature on 

 other genera of epiphytic algte, and thus arrive at a solution of 

 the question as to what becomes of them on the "seasonal dis- 

 appearance " of their hosts. 



The first of the new genera, Hecatoneina, is founded on Phyco- 



