F. Børgesen: List of species. 



441 



12. Colpoinenia simiosa (Roth) Derb, et Sol. 



13. Hydroclathrus cancellatus Bory. 



14. Rosenvini^ea Saiictæ Cnicis Borgs. 



In the description of this plant (vol. 1, p. 178) the locality 

 and occurrence has been omitted. It was found in shallow water 

 near the shore in a sheltered place this being protected from the 

 open sea by coral reefs. It was attached to small stones. It was 

 gathered in the month of January. 



St. Croix: Longford. 



15. Castagnea Zosteræ (Mohr) Thur. 



16. Myrionema vulgare Thur. 



Thuret, G., in Le J o lis, Liste des algues mar. de Cherbourg, p. 82. 

 Sauvageau, C, Sur quelques Myrionémacées (Ann. sc. nat., Bot., Sér. 8, 

 Tome 5, 1897, p. 185). 



Upon an old Sargassum, together with many other epi- 

 phytic and partly endophytic algæ, a Myrionema also occurred 

 which I think referable 

 to M. vulgare. 



Fig. 415 a shows a 

 part of the basal disc; it 

 consists of creeping fil- 

 aments whose cells are 

 from 5 to 7 ja thick. And 

 fig. 415 b shows pluri- 

 locular sporangia from 

 the older parts of the 

 plant; the sporangia are 

 about 7 |u thick. The hairs 

 have a rather long sheath 

 at their base; they are 

 about 7 — 8 IX thick. 



This plant was found 

 in the harbour of St. 

 Thomas. 



A very similar plant 

 was found upon Chætomorpha antennina gathered at »Northside«, 

 St. Croix in a very exposed place (Fig. 415 d). 



Fig. 415. Myrionema vulgare Thur. 



a, b, c, parts of a plant from St. Thomas, 



d, part of a plant from St. Croix, e, part of 



a plant from St. Jan. (a, 5, c, r/, about 275:1. 



e, about 200:1.) 



