8 Dansk Botanisk Arkiv, Bd. 2. Nr. 2. 



apex and base, reaching to a length of about 70 — 100 (i, and a 

 breadth of 15—20//. 



Unilocular sporangia were not found. 



Harvey's description and figure of this species being not 

 sufficiently good for an absolutely certain determination to be 

 made I have been very thankful to receive from Professor 

 Sauvageau some fine preparations of Harvey's original plant. 

 Compared with these my plant shows some differences, the most 

 essential of these being that the hairs in the West Indian plant 

 are more richly developed and the ramuli not so much attenuated 

 as in the original plant ; in the latter also the cells seem to be 

 somewhat more barrelshaped, while in mine they are most often 

 quite cylindrical. But I do not think that these differences are 

 of sufficient importance to separate my plant from Harvey's. 



As is well known it is rather doubtful how far Ectocarpus 

 virescens Thur. is a distinct species from that of Harvey. Of 

 this species also Prof. Sauvageau has been so kind as to send 

 me not only specimens from Herb. Thuret, but also some col- 

 lected by himself at Guéthary, one of which has plurilocular 

 sporangia with large spores, and other with small spores. 



Having compared these specimens with mine and also with 

 Harvey's plant I find that while the shape of the sporangia 

 agree well in all the specimens, the French material has more 

 attenuated branchlets and not such well developed hairs as in 

 mine. In this respect they agree with Harvey's. But in the 

 American plant and so also in mine we have not yet found more 

 than a single kind of plurilocular sporangia. Furthermore Ectoc. 

 Mitchellæ becomes somewhat more brownish in colour when dry 

 and seems also to be somewhat more rigid and robust as the 

 whole. 



At the Danish Islands this species was found in somewhat 

 exposed localities in the upper sublittoral region. 



St. Thomas: Several places in the harbour, Store Nordside Bugt. 

 Geogr. Distrib. Atlantic coast of North America. 



3. Ectocarpus coniferus nov. spec. 

 Ectocarpus mediocris, axi primario distincto, filamentis erectis, 

 rhizoideis brevibus substrato adfixis, ca. 40// crassis, articulis 1 /a 

 usque 4 plo longioribus quam latioribus, in parte basali simplicibus, 

 dein ramosis ramis irregulariter dispositis, interdum alternis, 

 secundis aut sparsis, curvatis, apicem versus attenuatis in pilum 

 longum articulatum productis. 



