NS 



that at least '>ne of these species was new to science but, owing to the kindness of Prof. 

 Lignier at Caen, I was allowed to study the type specimens of Lamouroux ; and this study 

 convinced me that my specimens belonged to species already described by Lamouroux as 

 A. foliacea and A. crassa. Tliis latter is an almost forgotten species described by Lamouroux 

 at the end of the zoological part of "Le voyage de 1'Uranie par Freycinet". 



My sections of A. foliacea showed that the cortical layer participated as a rule in the 

 formation of the node; it grew in thickness with the thickness of the frond, it was an integral 

 part of the node; the joint was often broader, but otherwise the only difference between node 

 and joint consisted in the former not being calcified. 



In A. crassa the central strand alone forms the node; its cells alone are non-calcified 

 and have thick membranes but the cortical layer persists; it has thin-walled calcified cells and 

 forms an integral part of the joint. In a small form of A. crassa the node was outwardly not 

 visible, and while sectioning this plant it often happened that the node feil out of the section ; 

 in dried plants the contact between node and cortical layer is very loose, because a layer of 

 cells that surrounds the node, tears very easily, the upper and under joint remaining connected 

 by the calcified cortical layer. In larger specimens with long joints the cortical layer splits 

 however horizontally leaving the node visible for a very short space. 



The specimens in Lamouroux's herbarium were rather flat, broad and palmate; I had 

 exactly the same specimens but also long, branched, spreading specimens, described by Grunow 

 as A. Godeffroyi and small compact ones, and all had their nodes built up after the same type. 



Ought I now to consider these specimens as different species or were they only different 

 forms of one species? To this question it appeared to me that my specimens of A. foliacea 

 cjave an answer. 



Of this latter species I had specimens exactly like those in the herbarium of Lamouroux, 

 others again that were much narrower and finally creeping ones with much broader winged 

 joints. I suppose that these are identical with the Amphiroa described by Grunow from Ovalau 

 in his paper on the "Algen der Fidschi, Tonga und Samoa Insein". Some of the branches of 

 these latter fronds instead of spreading horizontally grew in a vertical direction and when growing 

 erect the form of the branch changed. It grew narrow, almost cylindrical with a small wing 

 and differed totally from the creeping joints from which it sprang and also from the type of 

 Lamouroux (PI. XIV, fig. i — 8); they resembled and were in fact identical with the alga 

 named A. nobilis by Hauck in his paper "Ueber einige von Hildexbrandt im Rothen und 

 Indischen Ocean g-esammelte Alg-en. V". In all these branches the nodes were the same. This 

 led me to conclude that since : 



i 1 had been fortunate enough to collect specimens that showed in an undeniable way the 

 specitic identity of branches so different, that seen apart, one would think they ought to be 

 taken for different species, although they had the same anatomical structure of joint and node, 

 could show that different species showed great difference in the anatomical structure of 

 joint and node, 

 It was highly probable that species showing the same anatomical structure of joint and node 



>nged to one species. 



