316 
opercular apparatus, and the composition of the colony has referred 
the genus Idia not on ly to an independent family, but also to a 
new section Thalamophora. A correct description of the colony 
has been given by Bale 2 ), and Billard 3 ) has pointed out the 
presence of an adcauline operculum. 
Plate IV. 
Fig. 1. Sertularia Nuttingi n. sp. Hydrothecae from the distal portion 
of the colony. Frontal surface. X 57. 
— 2. The same species. Distal portion of the colony. Dorsal surface, 
X 47. 
— 3. The same species. The distal end of a hydrotheca, seen from 
the frontal surface. X 66. 
— 4. A gonotheca of the same species. X 34. 
— 5. The distal end of a hydrotheca of Sert. Fabricii Lev., seen from 
its frontal surface. X 47. 
— 6. The distal end of thej same hydrotheca, seen from the side. 
X 47. 
— 7. Sertularia intermedia n. sp. Hydrothecae from the distal por¬ 
tion of a colony. X 34. 
— 8. The same species. The distal end of a hydrotheca, seen from 
its frontal surface. X 66. 
— 9. The same species. The one side-half of the distal end of a hy¬ 
drotheca, extended. X 66. 
— 10. A gonotheca of the same species. X 34. 
— 11. Sertularia decipiens n. sp. A portion oi a branch, seen from 
the side. X 20. 
— 12. The same species. A portion of a branch. Front view. X 20. 
— 13. Sertularia pumila L. A pair of hydrothecae showing distinet 
stalks, and distally to each of them a translucent inner cavity. 
Trondhjem-fiord. X 34. 
— 14. The same species. Frontal view of the end of a hydrotheca 
X 66. 
— 15. The same species. Longitudinal section through a portion of a 
hydrotheca showing the stalk and the inner cavity between the 
latter and the hydrotheca. X 47. 
— 16. Sertularia Suensoni n. sp. A portion of a branch. Front 
view. X 34. 
2 ) 7 . 
3 ) 9. 
