Plate III. 



Vertical sections through the sphincter muscles. In the figs, i — 3, 5 the distal part of the sphincter is 



turned upwards, in the figs- 4 and 6 downwards. 

 Fig. 1 of Epizoanthus abyssorum 2 / 3 I . 



— 2 - — beerenislandicus 4/ 3 . 



3 - norvegicus (from Skarnsound) 2 / 3 . 



— 4 - — roseus 2 / 3 . 



— 5 - Isozoaiitlnts arborescens (from Ingolf Exp. St. 97) V 3 . 



— 6 - ParazocDitlius haddoni (from N. W. of Bergen, Mattson 1880 2 / 3 ). 



1 Magnifications refer to Reichert's system "Austria". Figures drawn on the level of the microscope's foot. 



