>70 ME. R. J. HAEYET GIBSON ON THE STRUCTURE 



Dr. Bornet informs me that he has never met with this rarity ; 

 and my friend Mr. Batters has been equally unfortunate. 



Mr. Butfham 



but he gives no 



description or figure. In a private letter Mr. Buffham in- 

 forms me that the material he collected was monoecious, but 

 that he hesitated to describe the structure of the cystocarp in 

 detail, not only because he had taken but little material, but also 

 because the appearances seemed to him u so extraordinary. 1 ' 



Dr. Bornet mentioned in his letter to me that Prof. Schmitz 

 had, he believed, examined specimens with cystocarps ; and I 

 accordingly entered into correspondence with that distinguished 

 algologist. Dr. Schmitz was so kind as to furnish me with notes 

 of his unpublished observations on specimens he had obtained 

 from the Berlin Herbarium in 1885, gathered on the coast of 

 Normandy, and at Ostend in the year 1832. I have to record 

 my thanks to Prof. Schmitz, not only for these notes, but also 

 for various critical remarks made on my MS. and drawings which 

 he was good enough to look over. These criticisms I shall have 

 occasion to refer to in the sequel. 



The structure of the vegetative organs has been frequently 

 described in many treatises ; I may briefly recapitulate the chief 

 features of that structure, as it will be thus more easy to elucidate 

 that of the reproductive organs. The antheridia have been already 

 figured by Buffham, and the tetraspores by Kiitzing and others. 

 I add a few notes on these organs, which my sections euabled me 

 to make out more clearly. 



Following the advice given to me by Mr. E. A. L. Batters, I 

 have gathered (or had sent to me) regularly for many months a 

 number of plants of O. Opuntia, in the hope that I might meet 

 with specimens of the cystocarpic fruit. In the end of October 

 of 1890, whilst on a visit to the Liverpool Marine Biological 

 Station on Puffin Island, N. Wales, I collected a considerable 

 quantity of the weed. It grows in that locality in abundance on 

 the protected faces of rocks near high-water mark. On exa- 

 mining my latest gathering on my return to Liverpool, I was 

 rewarded for my previous fruitless search by finding that many, 

 if not all the plants bore not only tetraspores but antheridia 

 and cystocarps as well. I sectionized a large number, and the 

 results of my investigation I have now the honour of laying before 

 the Society. 



* Quekett Micr. Club Journ. s*r 9, ni r» 9ii7 



