PLATE XXII. 



Halecium groenlandicum n. sp. 



Hg. 1. The lower part of the colony with the characteristic rhizome, 

 whose irregularly ramified tubes bear some hydrothecae and 

 gonothecae. The colony is growing on a Bryozoan, which is 

 only shadowed in the figure, x 11. 



— 2. The middle part of the stem from which arise closely rami- 



fied tubes bearing hydrothecae and gonothecae. x 11. 



— 3. A series of hydrothecae (a pseudohydrocaulus). x 40. 



— 4. A small branch from the rhizome with four gonothecae. x 18. 



