F. Børgesen: List of species. 421 



lating shape of the cells, the filaments get a serpentine-like ap- 

 pearance. 



The cylindrical part of the cells is about 4 fx thick, the swelled 

 part often more than 20 «. The cells reach a length of more 

 than 70 fi. 



The branches are mostly given off from the swelled parts 

 of the cells, and it may happen that 3 to 4 branches issue from 

 one and the same cell, this then becoming swelled and often very 

 irregularly shaped through nearly its whole length. The rami- 

 fication is rather irregular, but nevertheless a certain method is pre- 

 sent, because a main filament is, as a rule, distinguishable, and 

 from this branches are given off at about right angles on both 

 sides. In this way the plant forms a reticular tissue with larger 

 and smaller meshes all over the surface of the host. 



The shape of the chromatophore was not to be seen with 

 certainty in the material, but seems to be a parietal plate. There 

 are several large pyrenoids in each cell; the cells contain much 

 starch. 



The Chrysymenia, in which it occurred, was dredged in about 

 15 fathoms of water. 



St. Jan: off America Hill. 



13. Ulvella Leus Crouan. 



14. Pringsheimia scutata Reinke. 



15. — (?) Udoteæ Børgs. 



16. Gomontia polyrhiza (Lagerh.) Bornet et Flah. 



17. Chætomorpha clavata (Ag.) Kiitz. 



18. — antennina (Bory) Kiitz. 



19. — crassa (Ag.) Kiitz. 



20. — ærea (Dillw.) Kütz. 



21. — brachygona Harv. 



Besides the above mentioned (vol. I, p. 18) detached form 

 of this species I have found several fixed forms all characterized 

 by proportionally short cells, but of rather varying diameter 

 in the filaments; but, nevertheless, as it seems, closely connected. 

 How far these forms are rightly referred to Chætomorpha bra- 

 chygona I dare not say. A study upon living material of these 

 forms, which in several respects bear a close resemblance to Uro- 

 spora, would be highly interesting and instructive. 



