Plate I. 



Fig. i. Pliobothrus symmetricus; front surface of an intact colony from the "Ingolf" St. 55. Natural size. 



2. hind surface of the same colony. Nat. size. 



3. two ends of branches from "Ingolf St. 55. 4/ t . 



4. Stylastcr gemmascens; one of the type specimens of Giinnerus' Madrepora virginea from the 

 west coast of Norway. Nat. size. 



5. Stylaster gemmascens; front surface of an openly built colony from the Trondhjem Fjord. 



Nat size. 



6. Stylaster gemmascens; hind surface of same colony. Nat. size. 



7. front surface of the compact branch of a fertile colony ($) from the 



Trondhjem Fjord. Nat size. 

 8. Stylaster roseus\ front surface of a fragment of a colony from Angmagsalik with male ampullae 



Nat. size. 

 9. Stylaster roseus; hind surface of the same fragment. Nat size. 



