266 M. C. Montagne on Ctenodus Labillardieri. 



munication from Mr. Harvey has proved the truth of my suspicion; 

 and I take the earliest opportunity of informing you of it, that you 

 may be so kind as to complete the communication relative to the 

 very curious fructification of Fucus Labillardieri which you made 

 on a former occasion. This fructification has the same external 

 appearance as the other, and it is only on analysis that we find, 

 that instead of a considerable number of cells it has but one, which 

 opens by a pore at the summit. Among the admirable figures 

 in Kutzing's work, I do not find one capable of giving you an 

 idea of it, or I should be content with merely citing it. I am 

 going then to describe it as briefly as I can. Erom a central ax- 

 illary placenta a tuft of branched articulated filaments arises in 

 the form of a wheat-sheaf, whose coloured endochromes are rather 

 longer than broad. Their tint is faint below, but as they ap- 

 proach the summit of the tuft, the colour becomes brighter and 

 more purple. These are the last joints of the filaments in question, 

 whose endochromes become the spores. They are in form oblong, 

 resembling somewhat that of grape-stones. Measured by the 

 micrometer their length is from one to two centiemes of a milli- 

 metre, and their breadth from the two-hundredth to the hundredth 

 of a millimetre. They are of a beautiful purple and extremely 

 numerous. As they are formed at the summit of the filaments 

 and occupy the upper part of the cavity, we have the explanation 

 of the imperfect figure of Turner, incomplete I mean in this sense, 

 that the structure of his microscope did not allow him to see the 

 rest of the fructifying apparatus. You see then that this fructi- 

 fication does not differ from that which we find in many other 

 Floridece, and that without its remarkable tetrasporic fruit it would 

 not form a distinct genus. You will moreover observe that I was 

 not deceived in my anticipations, since chance has procured me 

 the knowledge of the other mode of reproduction, of whose ex- 

 istence I felt sure from analogy. I received a day or two since 

 a letter from M. Zanardini, a well-known phycologist of Venice, 

 in answer to my communication relative to Ctenodus : you will see 

 by the terms of his letter which I am going to translate, that the 

 specimen which he possesses of Fucus Labillardieri has the con- 

 ceptacular fruit. " I have examined attentively, - " he says, " your 

 recent labours on the genus Ctenodus. M. Diesing has given me 

 a magnificent specimen of this Alga. I have subjected to a scru- 

 pulous examination many capsules, and I have felt vexed at not 

 being able to observe the facts which your figures represent, 

 either as regards the plurality of cells, or the centripetal direc- 

 tion of the organs of fructification." It is clear, since he could 

 not observe them, that M. Zanardini had before him, not the form 

 figured by me, but the conceptacular form illustrated by Turner. 

 I do not like to let this opportunity escape of apprising you of 



