IX. 



ON THE STRUCTURE OF HYDROCLATHRUS 



BORY. 



HYDROCLATHRUS SINUOSUS Zanard. and H. canccllatus Bory have by 

 recent authors been separated from the group of the Asperococcoidece in 

 which they were formerly placed, partly on account of the structure of 

 their thallus, and partly because they have not yet been shown to possess 

 any other than plurilocular sporangia, while all those plants now placed 

 in the group of the Asperococcoidecs have, with one exception,* well- 

 defined unilocular sporangia only. 



I examined the plants because I have been unable to find any detailed 

 description of them, and also with a view to determining the method of 

 development of certain groups of hairs scattered abundantly over the sur- 

 face. These are, apparently, analogous to the so-called ' fasergriibchen 'f 

 or ' cryptostomata ' of the higher Fucacece, and it seemed possible that the 

 development of such simple forms might throw light on the origin of 

 structures which occur so generally throughout this group. 



The plants examined were collected at Anguilla by Mr. W. R. Elliott, 

 and in the Gulf of Manaar by Mr. Thurston ; I have only, therefore, been 

 able to describe specimens preserved in alcohol. 



* J. H. 'Rvfihscm., Journal of Botany. 1891 



t Throughout this and the succeeding paper, 'cryptostomata' will be used in place 

 of 'fasergriibchen.' Though there are objections to the term, these do not outweigh the 

 advantage of using an adopted term of classical derivation in place of a German word. (ED.) 



53 H 



