- 181 — 



and St. Jan near the Isle Gr. St. James, and near Maria Bluff at 

 St. Jan (Dr. Th. Mo r tense n) and on the north side of St. Jan 

 at Whistling Bay. 



Clirysymeuia J. Ag. 



Up to the present I have 5 species of this genus from the 

 Danish Islands. 



As to the anatomical structure, referring for details to the 

 description of each species, I shall only mention here that the 

 membrane of the hollow thallus consists of a bark layer and a 

 few (sometimes only one) layers of larger cells lining the cavity in 

 the interior. On the innerside of the large membrane cells we find 

 glands which are of different form and placed in different ways in 

 each species. 



Further in some of the species (of the species found namely: 

 Ch. Agardhii and Ch. ventricosa) we find in the interior of the 

 older part of the thallus irregularly bent, articulated, hyphse-like 

 filaments developed from the membrane cells. In the specimen of 

 Ch. ventricosa I have examined no filaments at all were to be 

 found in the young parts of the thallus; it was first towards the 

 middle of the plant and from here downwards that they occurred 

 richly. In the other species that I have met with: Ch. Uvaria, 

 Ch. pyriformis and Ch. Enteromorpha no filaments were present. 



In "Species Algarum", vol. II, pars 1, p. 210 J. Agardh in 

 his description of the genus also says the following: "Cellulse in- 

 timee in tubulosis disruptionis qusedam vestigia monstrant, quae a 

 tubo sensim inflato derivando videntur. Tubus insuper intus fills 

 sparsissimis articulatis dichotomis interno strato aliorum generum 

 comparandis percurritur". And in Engler und Prantl, "Natilrl. 

 Pflanzenfamilien", 1. Teil, Abt. 2, p. 403 in the diagnosis of the 



genus we find : "Mark in den hohlen Thallusabschnitten durch 



das starke Flachenwachstum der angrenzenden Rinde friihzeitig 

 aus einander gezerrt und in vereinzelte Zellen zerrissen, die 

 zumeist die Innenseite der Rinde dauernd anhaften als kleinere, 

 vielfach dri^isentragende Zellen". 



Whether such a bursting really does occur in the thallus as 

 suggested in these statements, seems to me rather improbable. To 

 begin with e. g. in Chrysymenia Uvaria, the quite young vesicles 

 are solid but very early during growth the cavity begins to be 

 formed, the tissue in the middle being more and more loosely con- 



